index.html (3.10): Add note about mips atomicity.h.

[official-gcc.git] / gcc / c-decl.c

/* Process declarations and variables for C compiler.
   Copyright (C) 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
   2001, 2002, 2003 Free Software Foundation, Inc.

This file is part of GCC.

GCC 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.

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

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

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

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "intl.h"
#include "tree.h"
#include "tree-inline.h"
#include "rtl.h"
#include "flags.h"
#include "function.h"
#include "output.h"
#include "expr.h"
#include "c-tree.h"
#include "toplev.h"
#include "ggc.h"
#include "tm_p.h"
#include "cpplib.h"
#include "target.h"
#include "debug.h"
#include "timevar.h"
#include "c-common.h"
#include "c-pragma.h"
#include "cgraph.h"

/* In grokdeclarator, distinguish syntactic contexts of declarators.  */
enum decl_context
{ NORMAL,                       /* Ordinary declaration */
  FUNCDEF,                      /* Function definition */
  PARM,                         /* Declaration of parm before function body */
  FIELD,                        /* Declaration inside struct or union */
  BITFIELD,                     /* Likewise but with specified width */
  TYPENAME};                    /* Typename (inside cast or sizeof)  */

\f
/* 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.  */
location_t pending_invalid_xref_location;

/* While defining an enum type, this is 1 plus the last enumerator
   constant value.  Note that will do not have to save this or `enum_overflow'
   around nested function definition since such a definition could only
   occur in an enum value expression and we don't use these variables in
   that case.  */

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.  */

static 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;

/* Similar, for the file and line that the prototype came from if this is
   an old-style definition.  */
static const char *current_function_prototype_file;
static int current_function_prototype_line;

/* The current statement tree.  */

static GTY(()) struct stmt_tree_s c_stmt_tree;

/* The current scope statement stack.  */

static GTY(()) tree c_scope_stmt_stack;

/* 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 GTY(()) tree named_labels;

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

static GTY(()) tree shadowed_labels;

/* A list of external DECLs that appeared at block scope when there was
   some other global meaning for that identifier.  */
static GTY(()) tree truly_local_externals;

/* 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, set to 1 if
   a call to a noreturn function is seen.  */

int current_function_returns_abnormally;

/* 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 when starting a function declared `extern inline'.  */

static int current_extern_inline;
\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.
 */

struct binding_level GTY(())
  {
    /* 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.
     */
    tree tags;

    /* For each level, a list of shadowed outer-level 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;

    /* For each level, a list of shadowed outer-level tag 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 ..._TYPE node).  */
    tree shadowed_tags;

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

    /* Nonzero if we are currently filling this level with parameter
       declarations.  */
    char parm_flag;

    /* Nonzero if this is the outermost block scope of a function body.
       This scope contains both the parameters and the local variables
       declared in the outermost block.  */
    char function_body;

    /* Nonzero means make a BLOCK for this level regardless of all else.  */
    char keep;

    /* Nonzero means make a BLOCK if this level has any subblocks.  */
    char keep_if_subblocks;

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

    /* A list of decls giving the (reversed) specified order of parms,
       not including any forward-decls in the parmlist.
       This is so we can put the parms in proper order for assign_parms.  */
    tree parm_order;
  };

#define NULL_BINDING_LEVEL (struct binding_level *) NULL

/* The binding level currently in effect.  */

static GTY(()) struct binding_level *current_binding_level;

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

static GTY((deletable (""))) 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 GTY(()) struct binding_level *global_binding_level;

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

static int keep_next_level_flag;

/* Nonzero means make a BLOCK for the next level pushed
   if it has subblocks.  */

static int keep_next_if_subblocks;

/* The chain of outer levels of label scopes.
   This uses the same data structure used for binding levels,
   but it works differently: each link in the chain records
   saved values of named_labels and shadowed_labels for
   a label binding level outside the current one.  */

static GTY(()) struct binding_level *label_level_chain;

/* Functions called automatically at the beginning and end of execution.  */

tree static_ctors, static_dtors;

/* Forward declarations.  */

static struct binding_level *make_binding_level         PARAMS ((void));
static void pop_binding_level           PARAMS ((struct binding_level **));
static int duplicate_decls              PARAMS ((tree, tree, int));
static int redeclaration_error_message  PARAMS ((tree, tree));
static void implicit_decl_warning       PARAMS ((tree));
static void storedecls                  PARAMS ((tree));
static void storetags                   PARAMS ((tree));
static tree lookup_tag                  PARAMS ((enum tree_code, tree, int));
static tree lookup_name_current_level   PARAMS ((tree));
static tree grokdeclarator              PARAMS ((tree, tree, enum decl_context,
                                                 int));
static tree grokparms                   PARAMS ((tree, int));
static void layout_array_type           PARAMS ((tree));
static tree c_make_fname_decl           PARAMS ((tree, int));
static void c_expand_body_1             PARAMS ((tree, int));
static tree any_external_decl           PARAMS ((tree));
static void record_external_decl        PARAMS ((tree));
static void warn_if_shadowing           PARAMS ((tree, tree));
static void clone_underlying_type       PARAMS ((tree));
static bool flexible_array_type_p       PARAMS ((tree));
\f
/* States indicating how grokdeclarator() should handle declspecs marked
   with __attribute__((deprecated)).  An object declared as
   __attribute__((deprecated)) suppresses warnings of uses of other
   deprecated items.  */
   
enum deprecated_states {
  DEPRECATED_NORMAL,
  DEPRECATED_SUPPRESS
};

static enum deprecated_states deprecated_state = DEPRECATED_NORMAL;

void
c_print_identifier (file, node, indent)
     FILE *file;
     tree node;
     int indent;
{
  print_node (file, "symbol", IDENTIFIER_SYMBOL_VALUE (node), indent + 4);
  print_node (file, "tag", IDENTIFIER_TAG_VALUE (node), indent + 4);
  print_node (file, "label", IDENTIFIER_LABEL_VALUE (node), indent + 4);
  if (C_IS_RESERVED_WORD (node))
    {
      tree rid = ridpointers[C_RID_CODE (node)];
      indent_to (file, indent + 4);
      fprintf (file, "rid ");
      fprintf (file, HOST_PTR_PRINTF, (void *)rid);
      fprintf (file, " \"%s\"", IDENTIFIER_POINTER (rid));
    }
}
\f
/* Hook called at end of compilation to assume 1 elt
   for a top-level tentative array defn that wasn't complete before.  */

void
c_finish_incomplete_decl (decl)
     tree decl;
{
  if (TREE_CODE (decl) == VAR_DECL)
    {
      tree type = TREE_TYPE (decl);
      if (type != error_mark_node
          && TREE_CODE (type) == ARRAY_TYPE
          && ! DECL_EXTERNAL (decl)
          && TYPE_DOMAIN (type) == 0)
        {
          warning_with_decl (decl, "array `%s' assumed to have one element");

          complete_array_type (type, NULL_TREE, 1);

          layout_decl (decl, 0);
        }
    }
}
\f
/* Reuse or create a struct for this binding level.  */

static struct binding_level *
make_binding_level ()
{
  struct binding_level *result;
  if (free_binding_level)
    {
      result = free_binding_level;
      free_binding_level = result->level_chain;
      memset (result, 0, sizeof(struct binding_level));
    }
  else
    result = (struct binding_level *)
      ggc_alloc_cleared (sizeof (struct binding_level));

  return result;
}

/* Remove a binding level from a list and add it to the level chain.  */

static void
pop_binding_level (lp)
     struct binding_level **lp;
{
  struct binding_level *l = *lp;
  *lp = l->level_chain;
  
  memset (l, 0, sizeof (struct binding_level));
  l->level_chain = free_binding_level;
  free_binding_level = l;
}

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

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

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->keep_if_subblocks
           && current_binding_level->blocks != 0)
          || current_binding_level->keep
          || current_binding_level->names != 0
          || current_binding_level->tags != 0);
}

/* Identify this binding level as a level of parameters.
   DEFINITION_FLAG is 1 for a definition, 0 for a declaration.
   But it turns out there is no way to pass the right value for
   DEFINITION_FLAG, so we ignore it.  */

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

/* Nonzero if currently making parm declarations.  */

int
in_parm_level_p ()
{
  return current_binding_level->parm_flag;
}

/* Enter a new binding level.  */

void
pushlevel (dummy)
     int dummy ATTRIBUTE_UNUSED;
{
  /* If this is the top level of a function, make sure that
     NAMED_LABELS is 0.  */

  if (current_binding_level == global_binding_level)
    named_labels = 0;

  if (keep_next_if_subblocks)
    {
      /* This is the transition from the parameters to the top level
         of the function body.  These are the same scope
         (C99 6.2.1p4,6) so we do not push another binding level.

         XXX Note kludge - keep_next_if_subblocks is set only by
         store_parm_decls, which in turn is called when and only
         when we are about to encounter the opening curly brace for
         the function body.  */
      current_binding_level->parm_flag = 0;
      current_binding_level->function_body = 1;
      current_binding_level->keep |= keep_next_level_flag;
      current_binding_level->keep_if_subblocks = 1;

      keep_next_level_flag = 0;
      keep_next_if_subblocks = 0;
    }
  else
    {
      struct binding_level *newlevel = make_binding_level ();

      newlevel->keep              = keep_next_level_flag;
      newlevel->level_chain       = current_binding_level;
      current_binding_level = newlevel;
      keep_next_level_flag = 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 is nonzero, this level had explicit declarations, so
   and create a "block" (a BLOCK node) for the level
   to record its declarations and subblocks for symbol table output.

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

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

tree
poplevel (keep, reverse, functionbody)
     int keep;
     int reverse;
     int functionbody;
{
  tree link;
  tree block;
  tree decl;
  tree decls = current_binding_level->names;
  tree tags = current_binding_level->tags;
  tree subblocks = current_binding_level->blocks;

  functionbody |= current_binding_level->function_body;
  keep |= (current_binding_level->keep || functionbody
           || (current_binding_level->keep_if_subblocks && subblocks != 0));

  /* We used to warn about unused variables in expand_end_bindings,
     i.e. while generating RTL.  But in function-at-a-time mode we may
     choose to never expand a function at all (e.g. auto inlining), so
     we do this explicitly now.  */
  warn_about_unused_variables (decls);

  /* Clear out the name-meanings declared on this level.
     Propagate TREE_ADDRESSABLE from nested functions to their
     containing functions.  */
  for (link = decls; link; link = TREE_CHAIN (link))
    {
      if (DECL_NAME (link) != 0)
        {
          if (DECL_EXTERNAL (link))
            /* External decls stay in the symbol-value slot but are
               inaccessible.  */
            C_DECL_INVISIBLE (link) = 1;
          else
            IDENTIFIER_SYMBOL_VALUE (DECL_NAME (link)) = 0;
        }

      if (TREE_CODE (link) == FUNCTION_DECL
          && ! TREE_ASM_WRITTEN (link)
          && DECL_INITIAL (link) != 0
          && TREE_ADDRESSABLE (link)
          && DECL_ABSTRACT_ORIGIN (link) != 0
          && DECL_ABSTRACT_ORIGIN (link) != link)
        TREE_ADDRESSABLE (DECL_ABSTRACT_ORIGIN (link)) = 1;
    }

  /* Clear out the tag-meanings declared on this level.  */
  for (link = tags; link; link = TREE_CHAIN (link))
    if (TREE_PURPOSE (link))
      IDENTIFIER_TAG_VALUE (TREE_PURPOSE (link)) = 0;

  /* 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_SYMBOL_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);

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

  for (link = current_binding_level->shadowed_tags; link;
       link = TREE_CHAIN (link))
    IDENTIFIER_TAG_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);

  /* If this is the top level block of a function, remove all
     PARM_DECLs from current_binding_level->names; they are already
     stored in DECL_ARGUMENTS of cfun->decl in proper order, should
     not be put in BLOCK_VARS, and furthermore reversing them will
     cause trouble later.  They are all together at the end of the
     list.  */
  if (functionbody && decls)
    {
      if (TREE_CODE (decls) == PARM_DECL)
        decls = 0;
      else
        {
          link = decls;
          while (TREE_CHAIN (link)
                 && TREE_CODE (TREE_CHAIN (link)) != PARM_DECL)
            link = TREE_CHAIN (link);

          TREE_CHAIN (link) = 0;
        }
    }

  /* 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)
    decls = nreverse (decls);

  /* 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 = 0;
  if (keep)
    {
      block = make_node (BLOCK);
      BLOCK_VARS (block) = decls;
      BLOCK_SUBBLOCKS (block) = subblocks;
      TREE_USED (block) = 1;
    }

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

  for (link = subblocks; link; link = TREE_CHAIN (link))
    BLOCK_SUPERCONTEXT (link) = block;

  /* Set the TYPE_CONTEXTs for all of the tagged types belonging to this
     binding contour so that they point to the appropriate construct, i.e.
     either to the current FUNCTION_DECL node, or else to the BLOCK node
     we just constructed.

     Note that for tagged types whose scope is just the formal parameter
     list for some function type specification, we can't properly set
     their TYPE_CONTEXTs here, because we don't have a pointer to the
     appropriate FUNCTION_TYPE node readily available to us.  For those
     cases, the TYPE_CONTEXTs of the relevant tagged type nodes get set
     in `grokdeclarator' as soon as we have created the FUNCTION_TYPE
     node which will represent the "scope" for these "parameter list local"
     tagged types.  */

  decl = functionbody ? current_function_decl : block;
  if (decl)
    for (link = tags; link; link = TREE_CHAIN (link))
      TYPE_CONTEXT (TREE_VALUE (link)) = decl;

  /* If the level being exited is the top level of a function, check
     over all the labels, and clear out the current (function local)
     meanings of their names. Then add them to BLOCK_VARS.  */

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

          if (DECL_INITIAL (label) == 0)
            {
              error_with_decl (label, "label `%s' used but not defined");
              /* Avoid crashing later.  */
              define_label (input_filename, input_line,
                            DECL_NAME (label));
            }
          else if (warn_unused_label && !TREE_USED (label))
            warning_with_decl (label, "label `%s' defined but not used");
          IDENTIFIER_LABEL_VALUE (DECL_NAME (label)) = 0;

          /* 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;
        }
    }

  /* Pop the current level, and free the structure for reuse.  */

  pop_binding_level (&current_binding_level);

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

  return block;
}

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

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

/* Set the BLOCK node for the innermost scope (the one we are
   currently in).  The RTL expansion machinery requires us to provide
   this hook, but it is not useful in function-at-a-time mode.  */

void
set_block (block)
     tree block ATTRIBUTE_UNUSED;
{
}
\f
void
push_label_level ()
{
  struct binding_level *newlevel;

  newlevel = make_binding_level ();

  /* Add this level to the front of the chain (stack) of label levels.  */

  newlevel->level_chain = label_level_chain;
  label_level_chain = newlevel;

  newlevel->names = named_labels;
  newlevel->shadowed = shadowed_labels;
  named_labels = 0;
  shadowed_labels = 0;
}

void
pop_label_level ()
{
  struct binding_level *level = label_level_chain;
  tree link, prev;

  /* Clear out the definitions of the declared labels in this level.
     Leave in the list any ordinary, non-declared labels.  */
  for (link = named_labels, prev = 0; link;)
    {
      if (C_DECLARED_LABEL_FLAG (TREE_VALUE (link)))
        {
          if (DECL_SOURCE_LINE (TREE_VALUE (link)) == 0)
            {
              error_with_decl (TREE_VALUE (link),
                               "label `%s' used but not defined");
              /* Avoid crashing later.  */
              define_label (input_filename, input_line,
                            DECL_NAME (TREE_VALUE (link)));
            }
          else if (warn_unused_label && !TREE_USED (TREE_VALUE (link)))
            warning_with_decl (TREE_VALUE (link),
                               "label `%s' defined but not used");
          IDENTIFIER_LABEL_VALUE (DECL_NAME (TREE_VALUE (link))) = 0;

          /* Delete this element from the list.  */
          link = TREE_CHAIN (link);
          if (prev)
            TREE_CHAIN (prev) = link;
          else
            named_labels = link;
        }
      else
        {
          prev = link;
          link = TREE_CHAIN (link);
        }
    }

  /* Bring back all the labels that were shadowed.  */
  for (link = shadowed_labels; link; link = TREE_CHAIN (link))
    if (DECL_NAME (TREE_VALUE (link)) != 0)
      IDENTIFIER_LABEL_VALUE (DECL_NAME (TREE_VALUE (link)))
        = TREE_VALUE (link);

  named_labels = chainon (named_labels, level->names);
  shadowed_labels = level->shadowed;

  /* Pop the current level, and free the structure for reuse.  */
  pop_binding_level (&label_level_chain);
}
\f
/* Push a definition or a declaration of struct, union or enum tag "name".
   "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 zero.  */

void
pushtag (name, type)
     tree name, type;
{
  struct binding_level *b = current_binding_level;

  if (name)
    {
      /* Record the identifier as the type's name if it has none.  */

      if (TYPE_NAME (type) == 0)
        TYPE_NAME (type) = name;

      if (IDENTIFIER_TAG_VALUE (name))
        b->shadowed_tags = tree_cons (name, IDENTIFIER_TAG_VALUE (name),
                                      b->shadowed_tags);
      IDENTIFIER_TAG_VALUE (name) = type;
    }

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

  /* 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.  */

  TYPE_STUB_DECL (type) = pushdecl (build_decl (TYPE_DECL, NULL_TREE, type));

  /* An approximation for now, so we can tell this is a function-scope tag.
     This will be updated in poplevel.  */
  TYPE_CONTEXT (type) = DECL_CONTEXT (TYPE_STUB_DECL (type));
}
\f
/* 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.

   When DIFFERENT_BINDING_LEVEL is true, NEWDECL is an external declaration,
   and OLDDECL is in an outer binding level and should thus not be changed.  */

static int
duplicate_decls (newdecl, olddecl, different_binding_level)
     tree newdecl, olddecl;
     int different_binding_level;
{
  int types_match = comptypes (TREE_TYPE (newdecl), TREE_TYPE (olddecl));
  int new_is_definition = (TREE_CODE (newdecl) == FUNCTION_DECL
                           && DECL_INITIAL (newdecl) != 0);
  tree oldtype = TREE_TYPE (olddecl);
  tree newtype = TREE_TYPE (newdecl);
  int errmsg = 0;

  if (DECL_P (olddecl))
    {
      if (TREE_CODE (newdecl) == FUNCTION_DECL
          && TREE_CODE (olddecl) == FUNCTION_DECL
          && (DECL_UNINLINABLE (newdecl) || DECL_UNINLINABLE (olddecl)))
        {
          if (DECL_DECLARED_INLINE_P (newdecl)
              && DECL_UNINLINABLE (newdecl)
              && lookup_attribute ("noinline", DECL_ATTRIBUTES (newdecl)))
            /* Already warned elsewhere.  */;
          else if (DECL_DECLARED_INLINE_P (olddecl)
                   && DECL_UNINLINABLE (olddecl)
                   && lookup_attribute ("noinline", DECL_ATTRIBUTES (olddecl)))
            /* Already warned.  */;
          else if (DECL_DECLARED_INLINE_P (newdecl)
                   && ! DECL_DECLARED_INLINE_P (olddecl)
                   && DECL_UNINLINABLE (olddecl)
                   && lookup_attribute ("noinline", DECL_ATTRIBUTES (olddecl)))
            {
              warning_with_decl (newdecl,
                                 "function `%s' redeclared as inline");
              warning_with_decl (olddecl,
                                 "previous declaration of function `%s' with attribute noinline");
            }
          else if (DECL_DECLARED_INLINE_P (olddecl)
                   && DECL_UNINLINABLE (newdecl)
                   && lookup_attribute ("noinline", DECL_ATTRIBUTES (newdecl)))
            {
              warning_with_decl (newdecl,
                                 "function `%s' redeclared with attribute noinline");
              warning_with_decl (olddecl,
                                 "previous declaration of function `%s' was inline");
            }
        }

      DECL_ATTRIBUTES (newdecl)
        = (*targetm.merge_decl_attributes) (olddecl, newdecl);
    }

  if (TREE_CODE (newtype) == ERROR_MARK
      || TREE_CODE (oldtype) == ERROR_MARK)
    types_match = 0;

  /* New decl is completely inconsistent with the old one =>
     tell caller to replace the old one.
     This is always an error except in the case of shadowing a builtin.  */
  if (TREE_CODE (olddecl) != TREE_CODE (newdecl))
    {
      if (TREE_CODE (olddecl) == FUNCTION_DECL
          && DECL_BUILT_IN (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.  */
          if (!TREE_PUBLIC (newdecl))
            {
              if (warn_shadow)
                warning_with_decl (newdecl, "shadowing built-in function `%s'");
            }
          else
            warning_with_decl (newdecl,
                               "built-in function `%s' declared as non-function");
        }
      else
        {
          error_with_decl (newdecl, "`%s' redeclared as different kind of symbol");
          error_with_decl (olddecl, "previous declaration of `%s'");
        }

      return 0;
    }

  /* For real parm decl following a forward decl, return 1 so old decl
     will be reused.  Only allow this to happen once.  */
  if (types_match && TREE_CODE (newdecl) == PARM_DECL
      && TREE_ASM_WRITTEN (olddecl) && ! TREE_ASM_WRITTEN (newdecl))
    {
      TREE_ASM_WRITTEN (olddecl) = 0;
      return 1;
    }

  /* The new declaration is the same kind of object as the old one.
     The declarations may partially match.  Print warnings if they don't
     match enough.  Ultimately, copy most of the information from the new
     decl to the old one, and keep using the old one.  */

  if (TREE_CODE (olddecl) == FUNCTION_DECL && DECL_BUILT_IN (olddecl))
    {
      /* A function declaration for a built-in function.  */
      if (!TREE_PUBLIC (newdecl))
        {
          /* If you declare a built-in function name as static, the
             built-in definition is overridden,
             but optionally warn this was a bad choice of name.  */
          if (warn_shadow)
            warning_with_decl (newdecl, "shadowing built-in function `%s'");
          /* Discard the old built-in function.  */
          return 0;
        }
      else if (!types_match)
        {
          /* Accept the return type of the new declaration if same modes.  */
          tree oldreturntype = TREE_TYPE (oldtype);
          tree newreturntype = TREE_TYPE (newtype);

          if (TYPE_MODE (oldreturntype) == TYPE_MODE (newreturntype))
            {
              /* Function types may be shared, so we can't just modify
                 the return type of olddecl's function type.  */
              tree trytype
                = build_function_type (newreturntype,
                                       TYPE_ARG_TYPES (oldtype));
              trytype = build_type_attribute_variant (trytype,
                                                      TYPE_ATTRIBUTES (oldtype));

              types_match = comptypes (newtype, trytype);
              if (types_match)
                oldtype = trytype;
            }
          /* Accept harmless mismatch in first argument type also.
             This is for the ffs and fprintf builtins.  */
          if (TYPE_ARG_TYPES (TREE_TYPE (newdecl)) != 0
              && TYPE_ARG_TYPES (oldtype) != 0
              && TREE_VALUE (TYPE_ARG_TYPES (newtype)) != 0
              && TREE_VALUE (TYPE_ARG_TYPES (oldtype)) != 0
              && (TYPE_MODE (TREE_VALUE (TYPE_ARG_TYPES (newtype)))
                  == TYPE_MODE (TREE_VALUE (TYPE_ARG_TYPES (oldtype)))))
            {
              /* Function types may be shared, so we can't just modify
                 the return type of olddecl's function type.  */
              tree trytype
                = build_function_type (TREE_TYPE (oldtype),
                                       tree_cons (NULL_TREE,
                                                  TREE_VALUE (TYPE_ARG_TYPES (newtype)),
                                                  TREE_CHAIN (TYPE_ARG_TYPES (oldtype))));
              trytype = build_type_attribute_variant (trytype,
                                                      TYPE_ATTRIBUTES (oldtype));

              types_match = comptypes (newtype, trytype);
              if (types_match)
                oldtype = trytype;
            }
          if (! different_binding_level)
            TREE_TYPE (olddecl) = oldtype;
        }
      else if (TYPE_ARG_TYPES (oldtype) == NULL
               && TYPE_ARG_TYPES (newtype) != NULL)
        {
          /* For bcmp, bzero, fputs the builtin type has arguments not
             specified.  Use the ones from the prototype so that type checking
             is done for them.  */
          tree trytype
            = build_function_type (TREE_TYPE (oldtype),
                                   TYPE_ARG_TYPES (newtype));
          trytype = build_type_attribute_variant (trytype,
                                                  TYPE_ATTRIBUTES (oldtype));

          oldtype = trytype;
          if (! different_binding_level)
            TREE_TYPE (olddecl) = oldtype;
        }
      if (!types_match)
        {
          /* If types don't match for a built-in, throw away the built-in.  */
          warning_with_decl (newdecl, "conflicting types for built-in function `%s'");
          return 0;
        }
    }
  else if (TREE_CODE (olddecl) == FUNCTION_DECL
           && DECL_SOURCE_LINE (olddecl) == 0)
    {
      /* A function declaration for a predeclared function
         that isn't actually built in.  */
      if (!TREE_PUBLIC (newdecl))
        {
          /* If you declare it as static, the
             default definition is overridden.  */
          return 0;
        }
      else if (!types_match)
        {
          /* If the types don't match, preserve volatility indication.
             Later on, we will discard everything else about the
             default declaration.  */
          TREE_THIS_VOLATILE (newdecl) |= TREE_THIS_VOLATILE (olddecl);
        }
    }
  /* Permit char *foo () to match void *foo (...) if not pedantic,
     if one of them came from a system header file.  */
  else if (!types_match
           && TREE_CODE (olddecl) == FUNCTION_DECL
           && TREE_CODE (newdecl) == FUNCTION_DECL
           && TREE_CODE (TREE_TYPE (oldtype)) == POINTER_TYPE
           && TREE_CODE (TREE_TYPE (newtype)) == POINTER_TYPE
           && (DECL_IN_SYSTEM_HEADER (olddecl)
               || DECL_IN_SYSTEM_HEADER (newdecl))
           && ((TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (newtype))) == void_type_node
                && TYPE_ARG_TYPES (oldtype) == 0
                && self_promoting_args_p (TYPE_ARG_TYPES (newtype))
                && TREE_TYPE (TREE_TYPE (oldtype)) == char_type_node)
               ||
               (TREE_TYPE (TREE_TYPE (newtype)) == char_type_node
                && TYPE_ARG_TYPES (newtype) == 0
                && self_promoting_args_p (TYPE_ARG_TYPES (oldtype))
                && TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (oldtype))) == void_type_node)))
    {
      if (pedantic)
        pedwarn_with_decl (newdecl, "conflicting types for `%s'");
      /* Make sure we keep void * as ret type, not char *.  */
      if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (oldtype))) == void_type_node)
        TREE_TYPE (newdecl) = newtype = oldtype;

      /* Set DECL_IN_SYSTEM_HEADER, so that if we see another declaration
         we will come back here again.  */
      DECL_IN_SYSTEM_HEADER (newdecl) = 1;
    }
  /* Permit void foo (...) to match int foo (...) if the latter is the
     definition and implicit int was used.  See c-torture/compile/920625-2.c.  */
  else if (!types_match && new_is_definition
           && TREE_CODE (olddecl) == FUNCTION_DECL
           && TREE_CODE (newdecl) == FUNCTION_DECL
           && TYPE_MAIN_VARIANT (TREE_TYPE (oldtype)) == void_type_node
           && TYPE_MAIN_VARIANT (TREE_TYPE (newtype)) == integer_type_node
           && C_FUNCTION_IMPLICIT_INT (newdecl))
    {
      pedwarn_with_decl (newdecl, "conflicting types for `%s'");
      /* Make sure we keep void as the return type.  */
      TREE_TYPE (newdecl) = newtype = oldtype;
      C_FUNCTION_IMPLICIT_INT (newdecl) = 0;
    }
  else if (!types_match
           /* Permit char *foo (int, ...); followed by char *foo ();
              if not pedantic.  */
           && ! (TREE_CODE (olddecl) == FUNCTION_DECL
                 && ! pedantic
                 /* Return types must still match.  */
                 && comptypes (TREE_TYPE (oldtype),
                               TREE_TYPE (newtype))
                 && TYPE_ARG_TYPES (newtype) == 0))
    {
      error_with_decl (newdecl, "conflicting types for `%s'");
      /* Check for function type mismatch
         involving an empty arglist vs a nonempty one.  */
      if (TREE_CODE (olddecl) == FUNCTION_DECL
          && comptypes (TREE_TYPE (oldtype),
                        TREE_TYPE (newtype))
          && ((TYPE_ARG_TYPES (oldtype) == 0
               && DECL_INITIAL (olddecl) == 0)
              ||
              (TYPE_ARG_TYPES (newtype) == 0
               && DECL_INITIAL (newdecl) == 0)))
        {
          /* Classify the problem further.  */
          tree t = TYPE_ARG_TYPES (oldtype);
          if (t == 0)
            t = TYPE_ARG_TYPES (newtype);
          for (; t; t = TREE_CHAIN (t))
            {
              tree type = TREE_VALUE (t);

              if (TREE_CHAIN (t) == 0
                  && TYPE_MAIN_VARIANT (type) != void_type_node)
                {
                  error ("a parameter list with an ellipsis can't match an empty parameter name list declaration");
                  break;
                }

              if (c_type_promotes_to (type) != type)
                {
                  error ("an argument type that has a default promotion can't match an empty parameter name list declaration");
                  break;
                }
            }
        }
      if (C_DECL_IMPLICIT (olddecl))
        error_with_decl (olddecl, "previous implicit declaration of `%s'");
      else
        error_with_decl (olddecl, "previous declaration of `%s'");

      /* This is safer because the initializer might contain references
         to variables that were declared between olddecl and newdecl. This
         will make the initializer invalid for olddecl in case it gets
         assigned to olddecl below.  */
      if (TREE_CODE (newdecl) == VAR_DECL)
        DECL_INITIAL (newdecl) = 0;
    }
  /* TLS cannot follow non-TLS declaration.  */
  else if (TREE_CODE (olddecl) == VAR_DECL && TREE_CODE (newdecl) == VAR_DECL
           && !DECL_THREAD_LOCAL (olddecl) && DECL_THREAD_LOCAL (newdecl))
    {
      error_with_decl (newdecl, "thread-local declaration of `%s' follows non thread-local declaration");
      error_with_decl (olddecl, "previous declaration of `%s'");
    }
  /* non-TLS declaration cannot follow TLS declaration.  */
  else if (TREE_CODE (olddecl) == VAR_DECL && TREE_CODE (newdecl) == VAR_DECL
           && DECL_THREAD_LOCAL (olddecl) && !DECL_THREAD_LOCAL (newdecl))
    {
      error_with_decl (newdecl, "non thread-local declaration of `%s' follows thread-local declaration");
      error_with_decl (olddecl, "previous declaration of `%s'");
    }
  else
    {
      errmsg = redeclaration_error_message (newdecl, olddecl);
      if (errmsg)
        {
          switch (errmsg)
            {
            case 1:
              error_with_decl (newdecl, "redefinition of `%s'");
              break;
            case 2:
              error_with_decl (newdecl, "redeclaration of `%s'");
              break;
            case 3:
              error_with_decl (newdecl, "conflicting declarations of `%s'");
              break;
            default:
              abort ();
            }

          error_with_decl (olddecl,
                           ((DECL_INITIAL (olddecl)
                             && current_binding_level == global_binding_level)
                            ? "`%s' previously defined here"
                            : "`%s' previously declared here"));
          return 0;
        }
      else if (TREE_CODE (newdecl) == TYPE_DECL
               && (DECL_IN_SYSTEM_HEADER (olddecl)
                   || DECL_IN_SYSTEM_HEADER (newdecl)))
        {
          warning_with_decl (newdecl, "redefinition of `%s'");
          warning_with_decl
            (olddecl,
             ((DECL_INITIAL (olddecl)
               && current_binding_level == global_binding_level)
              ? "`%s' previously defined here"
              : "`%s' previously declared here"));
        }
      else if (TREE_CODE (olddecl) == FUNCTION_DECL
               && DECL_INITIAL (olddecl) != 0
               && TYPE_ARG_TYPES (oldtype) == 0
               && TYPE_ARG_TYPES (newtype) != 0
               && TYPE_ACTUAL_ARG_TYPES (oldtype) != 0)
        {
          tree type, parm;
          int nargs;
          /* Prototype decl follows defn w/o prototype.  */

          for (parm = TYPE_ACTUAL_ARG_TYPES (oldtype),
               type = TYPE_ARG_TYPES (newtype),
               nargs = 1;
               ;
               parm = TREE_CHAIN (parm), type = TREE_CHAIN (type), nargs++)
            {
              if (TYPE_MAIN_VARIANT (TREE_VALUE (parm)) == void_type_node
                  && TYPE_MAIN_VARIANT (TREE_VALUE (type)) == void_type_node)
                {
                  warning_with_decl (newdecl, "prototype for `%s' follows");
                  warning_with_decl (olddecl, "non-prototype definition here");
                  break;
                }
              if (TYPE_MAIN_VARIANT (TREE_VALUE (parm)) == void_type_node
                  || TYPE_MAIN_VARIANT (TREE_VALUE (type)) == void_type_node)
                {
                  error_with_decl (newdecl,
                                   "prototype for `%s' follows and number of arguments doesn't match");
                  error_with_decl (olddecl, "non-prototype definition here");
                  errmsg = 1;
                  break;
                }
              /* Type for passing arg must be consistent
                 with that declared for the arg.  */
              if (! comptypes (TREE_VALUE (parm), TREE_VALUE (type)))
                {
                  error_with_decl (newdecl,
                                   "prototype for `%s' follows and argument %d doesn't match",
                                   nargs);
                  error_with_decl (olddecl, "non-prototype definition here");
                  errmsg = 1;
                  break;
                }
            }
        }
      /* Warn about mismatches in various flags.  */
      else
        {
          /* Warn if function is now inline
             but was previously declared not inline and has been called.  */
          if (TREE_CODE (olddecl) == FUNCTION_DECL
              && ! DECL_DECLARED_INLINE_P (olddecl)
              && DECL_DECLARED_INLINE_P (newdecl)
              && TREE_USED (olddecl))
            warning_with_decl (newdecl,
                               "`%s' declared inline after being called");
          if (TREE_CODE (olddecl) == FUNCTION_DECL
              && ! DECL_DECLARED_INLINE_P (olddecl)
              && DECL_DECLARED_INLINE_P (newdecl)
              && DECL_INITIAL (olddecl) != 0)
            warning_with_decl (newdecl,
                               "`%s' declared inline after its definition");

          /* If pedantic, warn when static declaration follows a non-static
             declaration.  Otherwise, do so only for functions.  */
          if ((pedantic || TREE_CODE (olddecl) == FUNCTION_DECL)
              && TREE_PUBLIC (olddecl)
              && !TREE_PUBLIC (newdecl))
            warning_with_decl (newdecl, "static declaration for `%s' follows non-static");

          /* If warn_traditional, warn when a non-static function
             declaration follows a static one.  */
          if (warn_traditional && !in_system_header
              && TREE_CODE (olddecl) == FUNCTION_DECL
              && !TREE_PUBLIC (olddecl)
              && TREE_PUBLIC (newdecl))
            warning_with_decl (newdecl, "non-static declaration for `%s' follows static");

          /* Warn when const declaration follows a non-const
             declaration, but not for functions.  */
          if (TREE_CODE (olddecl) != FUNCTION_DECL
              && !TREE_READONLY (olddecl)
              && TREE_READONLY (newdecl))
            warning_with_decl (newdecl, "const declaration for `%s' follows non-const");
          /* These bits are logically part of the type, for variables.
             But not for functions
             (where qualifiers are not valid ANSI anyway).  */
          else if (pedantic && TREE_CODE (olddecl) != FUNCTION_DECL
              && (TREE_READONLY (newdecl) != TREE_READONLY (olddecl)
                  || TREE_THIS_VOLATILE (newdecl) != TREE_THIS_VOLATILE (olddecl)))
            pedwarn_with_decl (newdecl, "type qualifiers for `%s' conflict with previous decl");
        }
    }

  /* Optionally warn about more than one declaration for the same name.  */
  if (errmsg == 0 && warn_redundant_decls && DECL_SOURCE_LINE (olddecl) != 0
      /* Don't warn about a function declaration
         followed by a definition.  */
      && !(TREE_CODE (newdecl) == FUNCTION_DECL && DECL_INITIAL (newdecl) != 0
           && DECL_INITIAL (olddecl) == 0)
      /* Don't warn about extern decl followed by (tentative) definition.  */
      && !(DECL_EXTERNAL (olddecl) && ! DECL_EXTERNAL (newdecl)))
    {
      warning_with_decl (newdecl, "redundant redeclaration of `%s' in same scope");
      warning_with_decl (olddecl, "previous declaration of `%s'");
    }

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

     Past this point, we don't change OLDTYPE and NEWTYPE
     even if we change the types of NEWDECL and OLDDECL.  */

  if (types_match)
    {
      /* When copying info to olddecl, we store into write_olddecl
         instead.  This allows us to avoid modifying olddecl when
         different_binding_level is true.  */
      tree write_olddecl = different_binding_level ? newdecl : olddecl;

      /* Merge the data types specified in the two decls.  */
      if (TREE_CODE (newdecl) != FUNCTION_DECL || !DECL_BUILT_IN (olddecl))
        {
          if (different_binding_level)
            {
              if (TYPE_ARG_TYPES (oldtype) != 0
                  && TYPE_ARG_TYPES (newtype) == 0)
                TREE_TYPE (newdecl) = common_type (newtype, oldtype);
              else
                TREE_TYPE (newdecl)
                  = build_type_attribute_variant
                    (newtype,
                     merge_attributes (TYPE_ATTRIBUTES (newtype),
                                       TYPE_ATTRIBUTES (oldtype)));
            }
          else
            TREE_TYPE (newdecl)
              = TREE_TYPE (olddecl)
                = common_type (newtype, oldtype);
        }

      /* Lay the type out, unless already done.  */
      if (oldtype != TREE_TYPE (newdecl))
        {
          if (TREE_TYPE (newdecl) != error_mark_node)
            layout_type (TREE_TYPE (newdecl));
          if (TREE_CODE (newdecl) != FUNCTION_DECL
              && TREE_CODE (newdecl) != TYPE_DECL
              && TREE_CODE (newdecl) != CONST_DECL)
            layout_decl (newdecl, 0);
        }
      else
        {
          /* Since the type is OLDDECL's, make OLDDECL's size go with.  */
          DECL_SIZE (newdecl) = DECL_SIZE (olddecl);
          DECL_SIZE_UNIT (newdecl) = DECL_SIZE_UNIT (olddecl);
          DECL_MODE (newdecl) = DECL_MODE (olddecl);
          if (TREE_CODE (olddecl) != FUNCTION_DECL)
            if (DECL_ALIGN (olddecl) > DECL_ALIGN (newdecl))
              {
                DECL_ALIGN (newdecl) = DECL_ALIGN (olddecl);
                DECL_USER_ALIGN (newdecl) |= DECL_ALIGN (olddecl);
              }
        }

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

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

      if (TREE_THIS_VOLATILE (newdecl))
        {
          TREE_THIS_VOLATILE (write_olddecl) = 1;
          if (TREE_CODE (newdecl) == VAR_DECL
              /* If an automatic variable is re-declared in the same
                 function scope, but the old declaration was not
                 volatile, make_var_volatile() would crash because the
                 variable would have been assigned to a pseudo, not a
                 MEM.  Since this duplicate declaration is invalid
                 anyway, we just skip the call.  */
              && errmsg == 0)
            make_var_volatile (newdecl);
        }

      /* Keep source location of definition rather than declaration.  */
      /* When called with different_binding_level set, keep the old
         information so that meaningful diagnostics can be given.  */
      if (DECL_INITIAL (newdecl) == 0 && DECL_INITIAL (olddecl) != 0
          && ! different_binding_level)
        {
          DECL_SOURCE_LINE (newdecl) = DECL_SOURCE_LINE (olddecl);
          DECL_SOURCE_FILE (newdecl) = DECL_SOURCE_FILE (olddecl);
        }

      /* Merge the unused-warning information.  */
      if (DECL_IN_SYSTEM_HEADER (olddecl))
        DECL_IN_SYSTEM_HEADER (newdecl) = 1;
      else if (DECL_IN_SYSTEM_HEADER (newdecl))
        DECL_IN_SYSTEM_HEADER (write_olddecl) = 1;

      /* Merge the initialization information.  */
      /* When called with different_binding_level set, don't copy over
         DECL_INITIAL, so that we don't accidentally change function
         declarations into function definitions.  */
      if (DECL_INITIAL (newdecl) == 0 && ! different_binding_level)
        DECL_INITIAL (newdecl) = DECL_INITIAL (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);

      /* Copy the assembler name.
         Currently, it can only be defined in the prototype.  */
      COPY_DECL_ASSEMBLER_NAME (olddecl, newdecl);

      if (TREE_CODE (newdecl) == FUNCTION_DECL)
        {
          DECL_STATIC_CONSTRUCTOR(newdecl) |= DECL_STATIC_CONSTRUCTOR(olddecl);
          DECL_STATIC_DESTRUCTOR (newdecl) |= DECL_STATIC_DESTRUCTOR (olddecl);
          DECL_NO_LIMIT_STACK (newdecl) |= DECL_NO_LIMIT_STACK (olddecl);
          DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (newdecl)
            |= DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (olddecl);
          TREE_THIS_VOLATILE (newdecl) |= TREE_THIS_VOLATILE (olddecl);
          TREE_READONLY (newdecl) |= TREE_READONLY (olddecl);
          DECL_IS_MALLOC (newdecl) |= DECL_IS_MALLOC (olddecl);
          DECL_IS_PURE (newdecl) |= DECL_IS_PURE (olddecl);
        }
    }
  /* If cannot merge, then use the new type and qualifiers,
     and don't preserve the old rtl.  */
  else if (! different_binding_level)
    {
      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.  */
  merge_weak (newdecl, olddecl);

  /* For functions, static overrides non-static.  */
  if (TREE_CODE (newdecl) == FUNCTION_DECL)
    {
      TREE_PUBLIC (newdecl) &= TREE_PUBLIC (olddecl);
      /* This is since we don't automatically
         copy the attributes of NEWDECL into OLDDECL.  */
      /* No need to worry about different_binding_level here because
         then TREE_PUBLIC (newdecl) was true.  */
      TREE_PUBLIC (olddecl) = TREE_PUBLIC (newdecl);
      /* If this clears `static', clear it in the identifier too.  */
      if (! TREE_PUBLIC (olddecl))
        TREE_PUBLIC (DECL_NAME (olddecl)) = 0;
    }
  if (DECL_EXTERNAL (newdecl))
    {
      if (! different_binding_level)
        {
          /* Don't mess with these flags on local externs; they remain
             external even if there's a declaration at file scope which
             isn't.  */
          TREE_STATIC (newdecl) = TREE_STATIC (olddecl);
          DECL_EXTERNAL (newdecl) = DECL_EXTERNAL (olddecl);
        }
      /* An extern decl does not override previous storage class.  */
      TREE_PUBLIC (newdecl) = TREE_PUBLIC (olddecl);
      if (! DECL_EXTERNAL (newdecl))
        DECL_CONTEXT (newdecl) = DECL_CONTEXT (olddecl);
    }
  else
    {
      TREE_STATIC (olddecl) = TREE_STATIC (newdecl);
      TREE_PUBLIC (olddecl) = TREE_PUBLIC (newdecl);
    }

  if (TREE_CODE (newdecl) == FUNCTION_DECL)
    {
      /* If we're redefining a function previously defined as extern
         inline, make sure we emit debug info for the inline before we
         throw it away, in case it was inlined into a function that hasn't
         been written out yet.  */
      if (new_is_definition && DECL_INITIAL (olddecl))
        {
          if (TREE_USED (olddecl))
            (*debug_hooks->outlining_inline_function) (olddecl);

          /* The new defn must not be inline.  */
          DECL_INLINE (newdecl) = 0;
          DECL_UNINLINABLE (newdecl) = 1;
        }
      else
        {
          /* If either decl says `inline', this fn is inline,
             unless its definition was passed already.  */
          if (DECL_DECLARED_INLINE_P (newdecl)
              || DECL_DECLARED_INLINE_P (olddecl))
            DECL_DECLARED_INLINE_P (newdecl) = 1;

          DECL_UNINLINABLE (newdecl) = DECL_UNINLINABLE (olddecl)
            = (DECL_UNINLINABLE (newdecl) || DECL_UNINLINABLE (olddecl));
        }

      if (DECL_BUILT_IN (olddecl))
        {
          /* Get rid of any built-in function if new arg types don't match it
             or if we have a function definition.  */
          if (! types_match || new_is_definition)
            {
              if (! different_binding_level)
                {
                  TREE_TYPE (olddecl) = TREE_TYPE (newdecl);
                  DECL_BUILT_IN_CLASS (olddecl) = NOT_BUILT_IN;
                }
            }
          else
            {
              /* If redeclaring a builtin function, and not a definition,
                 it stays built in.  */
              DECL_BUILT_IN_CLASS (newdecl) = DECL_BUILT_IN_CLASS (olddecl);
              DECL_FUNCTION_CODE (newdecl) = DECL_FUNCTION_CODE (olddecl);
            }
        }

      /* Also preserve various other info from the definition.  */
      if (! new_is_definition)
        {
          DECL_RESULT (newdecl) = DECL_RESULT (olddecl);
          /* When called with different_binding_level set, don't copy over
             DECL_INITIAL, so that we don't accidentally change function
             declarations into function definitions.  */
          if (! different_binding_level)
            DECL_INITIAL (newdecl) = DECL_INITIAL (olddecl);
          DECL_SAVED_INSNS (newdecl) = DECL_SAVED_INSNS (olddecl);
          DECL_SAVED_TREE (newdecl) = DECL_SAVED_TREE (olddecl);
          DECL_NUM_STMTS (newdecl) = DECL_NUM_STMTS (olddecl);
          DECL_ARGUMENTS (newdecl) = DECL_ARGUMENTS (olddecl);

          /* Set DECL_INLINE on the declaration if we've got a body
             from which to instantiate.  */
          if (DECL_INLINE (olddecl) && ! DECL_UNINLINABLE (newdecl))
            {
              DECL_INLINE (newdecl) = 1;
              DECL_ABSTRACT_ORIGIN (newdecl)
                = (different_binding_level
                   ? DECL_ORIGIN (olddecl)
                   : DECL_ABSTRACT_ORIGIN (olddecl));
            }
        }
      else
        {
          /* If a previous declaration said inline, mark the
             definition as inlinable.  */
          if (DECL_DECLARED_INLINE_P (newdecl)
              && ! DECL_UNINLINABLE (newdecl))
            DECL_INLINE (newdecl) = 1;
        }
    }
  if (different_binding_level)
    return 0;

  /* Copy most of the decl-specific fields of NEWDECL into OLDDECL.
     But preserve OLDDECL's DECL_UID.  */
  {
    unsigned olddecl_uid = DECL_UID (olddecl);

    memcpy ((char *) olddecl + sizeof (struct tree_common),
            (char *) newdecl + sizeof (struct tree_common),
            sizeof (struct tree_decl) - sizeof (struct tree_common));
    DECL_UID (olddecl) = olddecl_uid;
  }

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

  return 1;
}

/* Return any external DECL associated with ID, whether or not it is
   currently in scope.  */
static tree
any_external_decl (id)
     tree id;
{
  tree decl = IDENTIFIER_SYMBOL_VALUE (id);
  tree t;

  if (decl && TREE_CODE (decl) != TYPE_DECL && DECL_EXTERNAL (decl))
    return decl;

  t = purpose_member (id, truly_local_externals);
  if (t)
    return TREE_VALUE (t);

  return 0;
}

/* Record an external decl DECL.  This only does something if a
   shadowing decl already exists.  */
static void
record_external_decl (decl)
     tree decl;
{
  tree name = DECL_NAME (decl);
  if (!IDENTIFIER_SYMBOL_VALUE (name))
    return;

  truly_local_externals = tree_cons (name, decl, truly_local_externals);
}

/* Check whether decl-node X shadows an existing declaration.
   OLD is the old IDENTIFIER_SYMBOL_VALUE of the DECL_NAME of X,
   which might be a NULL_TREE.  */
static void
warn_if_shadowing (x, old)
     tree x, old;
{
  const char *name;

  /* Nothing to shadow?  */
  if (old == 0
      /* Shadow warnings not wanted?  */
      || !warn_shadow
      /* No shadow warnings for internally generated vars.  */
      || DECL_SOURCE_LINE (x) == 0
      /* No shadow warnings for vars made for inlining.  */
      || DECL_FROM_INLINE (x)
      /* Don't warn about the parm names in function declarator
         within a function declarator.
         It would be nice to avoid warning in any function
         declarator in a declaration, as opposed to a definition,
         but there is no way to tell it's not a definition.  */
      || (TREE_CODE (x) == PARM_DECL
          && current_binding_level->level_chain->parm_flag))
    return;

  name = IDENTIFIER_POINTER (DECL_NAME (x));

  if (TREE_CODE (old) == PARM_DECL)
    shadow_warning (SW_PARAM, name, old);
  else if (DECL_CONTEXT (old) == 0)
    shadow_warning (SW_GLOBAL, name, old);
  else
    shadow_warning (SW_LOCAL, name, old);
}


/* Subroutine of pushdecl.

   X is a TYPE_DECL for a typedef statement.  Create a brand new
   ..._TYPE node (which will be just a variant of the existing
   ..._TYPE node with identical properties) and then install X
   as the TYPE_NAME of this brand new (duplicate) ..._TYPE node.

   The whole point here is to end up with a situation where each
   and every ..._TYPE node the compiler creates will be uniquely
   associated with AT MOST one node representing a typedef name.
   This way, even though the compiler substitutes corresponding
   ..._TYPE nodes for TYPE_DECL (i.e. "typedef name") nodes very
   early on, later parts of the compiler can always do the reverse
   translation and get back the corresponding typedef name.  For
   example, given:

        typedef struct S MY_TYPE;
        MY_TYPE object;

   Later parts of the compiler might only know that `object' was of
   type `struct S' if it were not for code just below.  With this
   code however, later parts of the compiler see something like:

        struct S' == struct S
        typedef struct S' MY_TYPE;
        struct S' object;

    And they can then deduce (from the node for type struct S') that
    the original object declaration was:

                MY_TYPE object;

    Being able to do this is important for proper support of protoize,
    and also for generating precise symbolic debugging information
    which takes full account of the programmer's (typedef) vocabulary.

    Obviously, we don't want to generate a duplicate ..._TYPE node if
    the TYPE_DECL node that we are now processing really represents a
    standard built-in type.

    Since all standard types are effectively declared at line zero
    in the source file, we can easily check to see if we are working
    on a standard type by checking the current value of lineno.  */

static void
clone_underlying_type (x)
     tree x;
{
  if (DECL_SOURCE_LINE (x) == 0)
    {
      if (TYPE_NAME (TREE_TYPE (x)) == 0)
        TYPE_NAME (TREE_TYPE (x)) = x;
    }
  else if (TREE_TYPE (x) != error_mark_node
           && DECL_ORIGINAL_TYPE (x) == NULL_TREE)
    {
      tree tt = TREE_TYPE (x);
      DECL_ORIGINAL_TYPE (x) = tt;
      tt = build_type_copy (tt);
      TYPE_NAME (tt) = x;
      TREE_USED (tt) = TREE_USED (x);
      TREE_TYPE (x) = tt;
    }
}

/* 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;
{
  tree name = DECL_NAME (x);
  struct binding_level *scope = current_binding_level;

#ifdef ENABLE_CHECKING
  if (error_mark_node == 0)
    /* Called too early.  */
    abort ();
#endif

  /* Functions need the lang_decl data.  */
  if (TREE_CODE (x) == FUNCTION_DECL && ! DECL_LANG_SPECIFIC (x))
    DECL_LANG_SPECIFIC (x) = (struct lang_decl *)
      ggc_alloc_cleared (sizeof (struct lang_decl));

  /* A local extern declaration for a function doesn't constitute nesting.
     A local auto declaration does, since it's a forward decl
     for a nested function coming later.  */
  if ((TREE_CODE (x) == FUNCTION_DECL || TREE_CODE (x) == VAR_DECL)
      && DECL_INITIAL (x) == 0 && DECL_EXTERNAL (x))
    DECL_CONTEXT (x) = 0;
  else
    DECL_CONTEXT (x) = current_function_decl;

  if (name)
    {
      tree old;

      if (warn_nested_externs
          && scope != global_binding_level
          && DECL_EXTERNAL (x)
          && !DECL_IN_SYSTEM_HEADER (x))
        warning ("nested extern declaration of `%s'",
                 IDENTIFIER_POINTER (name));

      old = lookup_name_current_level (name);
      if (old && duplicate_decls (x, old, 0))
        return old;
      if (DECL_EXTERNAL (x) || scope == global_binding_level)
        {
          /* Find and check against a previous, not-in-scope, external
             decl for this identifier.  (C99 s???: If two declarations
             with external linkage, referring to the same object, have
             incompatible types, the behavior is undefined).  */
          tree ext = any_external_decl (name);
          if (ext)
            {
              if (duplicate_decls (x, ext, scope != global_binding_level))
                x = copy_node (ext);
            }
          else
            record_external_decl (x);
        }
          
      if (TREE_CODE (x) == TYPE_DECL)
        clone_underlying_type (x);

      /* If storing a local value, there may already be one
         (inherited).  If so, record it for restoration when this
         binding level ends.  Take care not to do this if we are
         replacing an older decl in the same binding level (i.e.
         duplicate_decls returned false, above).  */
      if (scope != global_binding_level
          && IDENTIFIER_SYMBOL_VALUE (name)
          && IDENTIFIER_SYMBOL_VALUE (name) != old)
        {
          warn_if_shadowing (x, IDENTIFIER_SYMBOL_VALUE (name));
          scope->shadowed = tree_cons (name, IDENTIFIER_SYMBOL_VALUE (name),
                                       scope->shadowed);
        }

      /* Install the new declaration in the requested binding level.  */
      IDENTIFIER_SYMBOL_VALUE (name) = x;
      C_DECL_INVISIBLE (x) = 0;

      /* Keep list of variables in this level with incomplete type.
         If the input is erroneous, we can have error_mark in the type
         slot (e.g. "f(void a, ...)") - that doesn't count as an
         incomplete type.  */
      if (TREE_TYPE (x) != error_mark_node
          && !COMPLETE_TYPE_P (TREE_TYPE (x)))
        {
          tree element = TREE_TYPE (x);

          while (TREE_CODE (element) == ARRAY_TYPE)
            element = TREE_TYPE (element);
          if (TREE_CODE (element) == RECORD_TYPE
              || TREE_CODE (element) == UNION_TYPE)
            scope->incomplete_list = tree_cons (NULL_TREE, x,
                                                scope->incomplete_list);
        }
    }

  /* Put decls on list in reverse order.
     We will reverse them later if necessary.  */
  TREE_CHAIN (x) = scope->names;
  scope->names = x;

  return x;
}

/* Record X as belonging to the global scope (C99 "file scope").
   This is used only internally by the Objective C front end,
   and is limited to its needs.  It will hork if there is _any_
   visible binding for X (not just a global one).  */
tree
pushdecl_top_level (x)
     tree x;
{
  tree name, old;

  if (TREE_CODE (x) != VAR_DECL)
    abort ();

  name = DECL_NAME (x);
  old = IDENTIFIER_SYMBOL_VALUE (name);

  if (old)
    {
      if (DECL_CONTEXT (old))
        abort ();

      if (!duplicate_decls (x, old, 0))
        abort ();

      return old;
    }

  DECL_CONTEXT (x) = 0;
  IDENTIFIER_SYMBOL_VALUE (name) = x;
  TREE_CHAIN (x) = global_binding_level->names;
  global_binding_level->names = x;
  return x;
}

/* Record X as belonging to the outermost scope of the current
   function.  This is used only internally, by c_make_fname_decl and
   build_external_ref, and is limited to their needs.  The NAME is
   provided as a separate argument because build_external_ref wants to
   use error_mark_node for X.  For VAR_DECLs, duplicate_decls is not
   called; if there is any preexisting decl for this identifier, it is
   an ICE.  */
tree
pushdecl_function_level (x, name)
     tree x;
     tree name;
{
  struct binding_level *scope;

  scope = current_binding_level;
  while (scope->function_body == 0)
    scope = scope->level_chain;
  if (!scope)
    abort ();

  if (x == error_mark_node)
    scope->shadowed = tree_cons (name, IDENTIFIER_SYMBOL_VALUE (name),
                                 scope->shadowed);
  else if (TREE_CODE (x) == VAR_DECL)
    {
      if (name != DECL_NAME (x))
        abort ();
      if (IDENTIFIER_SYMBOL_VALUE (name))
        abort ();

      DECL_CONTEXT (x) = current_function_decl;
      TREE_CHAIN (x) = scope->names;
      scope->names = x;
    }

  IDENTIFIER_SYMBOL_VALUE (name) = x;
  return x;
}
\f
/* Generate an implicit declaration for identifier FUNCTIONID as a
   function of type int ().  */

tree
implicitly_declare (functionid)
     tree functionid;
{
  tree decl = any_external_decl (functionid);

  if (decl && decl != error_mark_node)
    {
      /* Implicit declaration of a function already declared
         (somehow) in a different scope, or as a built-in.
         If this is the first time this has happened, warn;
         then recycle the old declaration.  */
      if (!C_DECL_IMPLICIT (decl))
        {
          implicit_decl_warning (DECL_NAME (decl));
          if (DECL_CONTEXT (decl))
            warning_with_decl (decl, "previous declaration of `%s'");
          C_DECL_IMPLICIT (decl) = 1;
        }
      /* If this function is global, then it must already be in the
         global binding level, so there's no need to push it again.  */
      if (current_binding_level == global_binding_level)
        return decl;
      /* If this is a local declaration, make a copy; we can't have
         the same DECL listed in two different binding levels.  */
      return pushdecl (copy_node (decl));
    }

  /* Not seen before.  */
  decl = build_decl (FUNCTION_DECL, functionid, default_function_type);
  DECL_EXTERNAL (decl) = 1;
  TREE_PUBLIC (decl) = 1;
  C_DECL_IMPLICIT (decl) = 1;
  implicit_decl_warning (functionid);

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

  /* No need to call objc_check_decl here - it's a function type.  */
  rest_of_decl_compilation (decl, NULL, 0, 0);

  /* Write a record describing this implicit function declaration to the
     prototypes file (if requested).  */

  gen_aux_info_record (decl, 0, 1, 0);

  /* Possibly apply some default attributes to this implicit declaration.  */
  decl_attributes (&decl, NULL_TREE, 0);

  return decl;
}

static void
implicit_decl_warning (id)
     tree id;
{
  const char *name = IDENTIFIER_POINTER (id);
  if (mesg_implicit_function_declaration == 2)
    error ("implicit declaration of function `%s'", name);
  else if (mesg_implicit_function_declaration == 1)
    warning ("implicit declaration of function `%s'", name);
}

/* 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 1 if NEWDECL is a redefinition, 2 if it is a redeclaration,
   and 3 if it is a conflicting declaration.  */

static int
redeclaration_error_message (newdecl, olddecl)
     tree newdecl, olddecl;
{
  if (TREE_CODE (newdecl) == TYPE_DECL)
    {
      /* Do not complain about type redeclarations where at least one
         declaration was in a system header.  */
      if (DECL_IN_SYSTEM_HEADER (olddecl) || DECL_IN_SYSTEM_HEADER (newdecl))
        return 0;
      return 1;
    }
  else if (TREE_CODE (newdecl) == FUNCTION_DECL)
    {
      /* Declarations of functions can insist on internal linkage
         but they can't be inconsistent with internal linkage,
         so there can be no error on that account.
         However defining the same name twice is no good.  */
      if (DECL_INITIAL (olddecl) != 0 && DECL_INITIAL (newdecl) != 0
          /* However, defining once as extern inline and a second
             time in another way is ok.  */
          && ! (DECL_DECLARED_INLINE_P (olddecl) && DECL_EXTERNAL (olddecl)
               && ! (DECL_DECLARED_INLINE_P (newdecl)
                     && DECL_EXTERNAL (newdecl))))
        return 1;
      return 0;
    }
  else if (DECL_CONTEXT (newdecl) == NULL_TREE)
    {
      /* 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.  */
      if (DECL_INITIAL (olddecl) != 0 && DECL_INITIAL (newdecl) != 0)
        return 1;
      /* Now we have two tentative defs, or one tentative and one real def.  */
      /* Insist that the linkage match.  */
      if (TREE_PUBLIC (olddecl) != TREE_PUBLIC (newdecl))
        return 3;
      return 0;
    }
  else if (current_binding_level->parm_flag
           && TREE_ASM_WRITTEN (olddecl) && !TREE_ASM_WRITTEN (newdecl))
    return 0;
  else
    {
      /* Newdecl has block scope.  If olddecl has block scope also, then
         reject two definitions, and reject a definition together with an
         external reference.  Otherwise, it is OK, because newdecl must
         be an extern reference to olddecl.  */
      if (!(DECL_EXTERNAL (newdecl) && DECL_EXTERNAL (olddecl))
          && DECL_CONTEXT (newdecl) == DECL_CONTEXT (olddecl))
        return 2;
      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;
{
  tree decl = IDENTIFIER_LABEL_VALUE (id);

  if (current_function_decl == 0)
    {
      error ("label %s referenced outside of any function",
             IDENTIFIER_POINTER (id));
      return 0;
    }

  /* Use a label already defined or ref'd with this name.  */
  if (decl != 0)
    {
      /* 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);

  /* 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_LOCATION (decl) = input_location;

  IDENTIFIER_LABEL_VALUE (id) = decl;

  named_labels = tree_cons (NULL_TREE, decl, named_labels);

  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;
{
  tree decl = IDENTIFIER_LABEL_VALUE (name);

  if (decl != 0)
    {
      tree dup;

      /* Check to make sure that the label hasn't already been declared
         at this label scope */
      for (dup = named_labels; dup; dup = TREE_CHAIN (dup))
        if (TREE_VALUE (dup) == decl)
          {
            error ("duplicate label declaration `%s'",
                   IDENTIFIER_POINTER (name));
            error_with_decl (TREE_VALUE (dup),
                             "this is a previous declaration");
            /* Just use the previous declaration.  */
            return lookup_label (name);
          }

      shadowed_labels = tree_cons (NULL_TREE, decl, shadowed_labels);
      IDENTIFIER_LABEL_VALUE (name) = decl = 0;
    }

  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)
     const char *filename;
     int line;
     tree name;
{
  tree decl = lookup_label (name);

  /* If label with this name is known from an outer context, shadow it.  */
  if (decl != 0 && DECL_CONTEXT (decl) != current_function_decl)
    {
      shadowed_labels = tree_cons (NULL_TREE, decl, shadowed_labels);
      IDENTIFIER_LABEL_VALUE (name) = 0;
      decl = lookup_label (name);
    }

  if (warn_traditional && !in_system_header && lookup_name (name))
    warning_with_file_and_line (filename, line,
                                "traditional C lacks a separate namespace for labels, identifier `%s' conflicts",
                                IDENTIFIER_POINTER (name));

  if (DECL_INITIAL (decl) != 0)
    {
      error_with_file_and_line (filename, line, "duplicate label `%s'",
                                IDENTIFIER_POINTER (name));
      return 0;
    }
  else
    {
      /* 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;
      return decl;
    }
}
\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.
   If THISLEVEL_ONLY is nonzero, searches only the current_binding_level.
   CODE 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, an error is reported.  */

static tree
lookup_tag (code, name, thislevel_only)
     enum tree_code code;
     tree name;
     int thislevel_only;
{
  tree tag = IDENTIFIER_TAG_VALUE (name);
  int thislevel = 0;

  if (!tag)
    return 0;

  /* We only care about whether it's in this level if
     thislevel_only was set or it might be a type clash.  */
  if (thislevel_only || TREE_CODE (tag) != code)
    {
      if (current_binding_level == global_binding_level
          || purpose_member (name, current_binding_level->tags))
        thislevel = 1;
    }

  if (thislevel_only && !thislevel)
    return 0;

  if (TREE_CODE (tag) != code)
    {
      /* Definition isn't the kind we were looking for.  */
      pending_invalid_xref = name;
      pending_invalid_xref_location = input_location;

      /* If in the same binding level as a declaration as a tag
         of a different type, this must not be allowed to
         shadow that tag, so give the error immediately.
         (For example, "struct foo; union foo;" is invalid.)  */
      if (thislevel)
        pending_xref_error ();
    }
  return tag;
}

/* Print an error message now
   for a recent invalid struct, union or enum cross reference.
   We don't print them immediately because they are not invalid
   when used in the `struct foo;' construct for shadowing.  */

void
pending_xref_error ()
{
  if (pending_invalid_xref != 0)
    error_with_file_and_line (pending_invalid_xref_location.file,
                              pending_invalid_xref_location.line,
                              "`%s' defined as wrong kind of tag",
                              IDENTIFIER_POINTER (pending_invalid_xref));
  pending_invalid_xref = 0;
}

\f
/* Look up NAME in the current binding level and its superiors
   in the namespace of variables, functions and typedefs.
   Return a ..._DECL node of some kind representing its definition,
   or return 0 if it is undefined.  */

tree
lookup_name (name)
     tree name;
{
  tree decl = IDENTIFIER_SYMBOL_VALUE (name);
  if (decl == 0 || decl == error_mark_node)
    return decl;
  if (C_DECL_INVISIBLE (decl))
    return 0;
  return decl;
}

/* Similar to `lookup_name' but look only at the current binding level.  */

static tree
lookup_name_current_level (name)
     tree name;
{
  tree decl = IDENTIFIER_SYMBOL_VALUE (name);

  if (decl == 0 || decl == error_mark_node || C_DECL_INVISIBLE (decl))
    return 0;

  if (current_binding_level == global_binding_level)
    return decl;

  /* Scan the current scope for a decl with name NAME.  */
  if (chain_member (decl, current_binding_level->names))
    return decl;

  return 0;
}
\f
/* Create the predefined scalar types of C,
   and some nodes representing standard constants (0, 1, (void *) 0).
   Initialize the global binding level.
   Make definitions for built-in primitive functions.  */

void
c_init_decl_processing ()
{
  tree endlink;
  tree ptr_ftype_void, ptr_ftype_ptr;

  /* Adds some ggc roots, and reserved words for c-parse.in.  */
  c_parse_init ();

  current_function_decl = NULL;
  named_labels = NULL;
  current_binding_level = NULL_BINDING_LEVEL;
  free_binding_level = NULL_BINDING_LEVEL;

  /* Make the binding_level structure for global names.  */
  pushlevel (0);
  global_binding_level = current_binding_level;

  build_common_tree_nodes (flag_signed_char);

  c_common_nodes_and_builtins ();

  boolean_type_node = integer_type_node;
  boolean_true_node = integer_one_node;
  boolean_false_node = integer_zero_node;

  c_bool_type_node = make_unsigned_type (BOOL_TYPE_SIZE);
  TREE_SET_CODE (c_bool_type_node, BOOLEAN_TYPE);
  TYPE_MAX_VALUE (c_bool_type_node) = build_int_2 (1, 0);
  TREE_TYPE (TYPE_MAX_VALUE (c_bool_type_node)) = c_bool_type_node;
  TYPE_PRECISION (c_bool_type_node) = 1;
  pushdecl (build_decl (TYPE_DECL, get_identifier ("_Bool"),
                        c_bool_type_node));
  c_bool_false_node = build_int_2 (0, 0);
  TREE_TYPE (c_bool_false_node) = c_bool_type_node;
  c_bool_true_node = build_int_2 (1, 0);
  TREE_TYPE (c_bool_true_node) = c_bool_type_node;

  endlink = void_list_node;
  ptr_ftype_void = build_function_type (ptr_type_node, endlink);
  ptr_ftype_ptr
    = build_function_type (ptr_type_node,
                           tree_cons (NULL_TREE, ptr_type_node, endlink));

  pedantic_lvalues = pedantic;

  make_fname_decl = c_make_fname_decl;
  start_fname_decls ();
}

/* Create the VAR_DECL for __FUNCTION__ etc. ID is the name to give the
   decl, NAME is the initialization string and TYPE_DEP indicates whether
   NAME depended on the type of the function.  As we don't yet implement
   delayed emission of static data, we mark the decl as emitted
   so it is not placed in the output.  Anything using it must therefore pull
   out the STRING_CST initializer directly.  This does mean that these names
   are string merging candidates, which is wrong for C99's __func__.  FIXME.  */

static tree
c_make_fname_decl (id, type_dep)
     tree id;
     int type_dep;
{
  const char *name = fname_as_string (type_dep);
  tree decl, type, init;
  size_t length = strlen (name);

  type =  build_array_type
          (build_qualified_type (char_type_node, TYPE_QUAL_CONST),
           build_index_type (size_int (length)));

  decl = build_decl (VAR_DECL, id, type);
  
  TREE_STATIC (decl) = 1;
  TREE_READONLY (decl) = 1;
  DECL_ARTIFICIAL (decl) = 1;
  
  init = build_string (length + 1, name);
  TREE_TYPE (init) = type;
  DECL_INITIAL (decl) = init;

  TREE_USED (decl) = 1;

  if (current_function_decl)
    pushdecl_function_level (decl, DECL_NAME (decl));

  finish_decl (decl, init, NULL_TREE);

  return decl;
}

/* Return a definition for a builtin function named NAME and whose data type
   is TYPE.  TYPE should be a function type with argument types.
   FUNCTION_CODE tells later passes how to compile calls to this function.
   See tree.h for its possible values.

   If LIBRARY_NAME is nonzero, use that for DECL_ASSEMBLER_NAME,
   the name to be called if we can't opencode the function.  If
   ATTRS is nonzero, use that for the function's attribute list.  */

tree
builtin_function (name, type, function_code, class, library_name, attrs)
     const char *name;
     tree type;
     int function_code;
     enum built_in_class class;
     const char *library_name;
     tree attrs;
{
  tree decl = build_decl (FUNCTION_DECL, get_identifier (name), type);
  DECL_EXTERNAL (decl) = 1;
  TREE_PUBLIC (decl) = 1;
  if (library_name)
    SET_DECL_ASSEMBLER_NAME (decl, get_identifier (library_name));
  make_decl_rtl (decl, NULL);
  pushdecl (decl);
  DECL_BUILT_IN_CLASS (decl) = class;
  DECL_FUNCTION_CODE (decl) = function_code;

  /* Warn if a function in the namespace for users
     is used without an occasion to consider it declared.  */
  if (name[0] != '_' || name[1] != '_')
    C_DECL_INVISIBLE (decl) = 1;

  /* Possibly apply some default attributes to this built-in function.  */
  if (attrs)
    decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
  else
    decl_attributes (&decl, NULL_TREE, 0);

  return decl;
}

/* Apply default attributes to a function, if a system function with default
   attributes.  */

void
c_insert_default_attributes (decl)
     tree decl;
{
  if (!TREE_PUBLIC (decl))
    return;
  c_common_insert_default_attributes (decl);
}
\f
/* Called when a declaration is seen that contains no names to declare.
   If its type is a reference to a structure, union or enum inherited
   from a containing scope, shadow that tag name for the current scope
   with a forward reference.
   If its type defines a new named structure or union
   or defines an enum, it is valid but we need not do anything here.
   Otherwise, it is an error.  */

void
shadow_tag (declspecs)
     tree declspecs;
{
  shadow_tag_warned (declspecs, 0);
}

void
shadow_tag_warned (declspecs, warned)
     tree declspecs;
     int warned;
     /* 1 => we have done a pedwarn.  2 => we have done a warning, but
        no pedwarn.  */
{
  int found_tag = 0;
  tree link;
  tree specs, attrs;

  pending_invalid_xref = 0;

  /* Remove the attributes from declspecs, since they will confuse the
     following code.  */
  split_specs_attrs (declspecs, &specs, &attrs);

  for (link = specs; link; link = TREE_CHAIN (link))
    {
      tree value = TREE_VALUE (link);
      enum tree_code code = TREE_CODE (value);

      if (code == RECORD_TYPE || code == UNION_TYPE || code == ENUMERAL_TYPE)
        /* Used to test also that TYPE_SIZE (value) != 0.
           That caused warning for `struct foo;' at top level in the file.  */
        {
          tree name = TYPE_NAME (value);
          tree t;

          found_tag++;

          if (name == 0)
            {
              if (warned != 1 && code != ENUMERAL_TYPE)
                /* Empty unnamed enum OK */
                {
                  pedwarn ("unnamed struct/union that defines no instances");
                  warned = 1;
                }
            }
          else
            {
              t = lookup_tag (code, name, 1);

              if (t == 0)
                {
                  t = make_node (code);
                  pushtag (name, t);
                }
            }
        }
      else
        {
          if (!warned && ! in_system_header)
            {
              warning ("useless keyword or type name in empty declaration");
              warned = 2;
            }
        }
    }

  if (found_tag > 1)
    error ("two types specified in one empty declaration");

  if (warned != 1)
    {
      if (found_tag == 0)
        pedwarn ("empty declaration");
    }
}
\f
/* Construct an array declarator.  EXPR is the expression inside [], or
   NULL_TREE.  QUALS are the type qualifiers inside the [] (to be applied
   to the pointer to which a parameter array is converted).  STATIC_P is
   nonzero if "static" is inside the [], zero otherwise.  VLA_UNSPEC_P
   is nonzero is the array is [*], a VLA of unspecified length which is
   nevertheless a complete type (not currently implemented by GCC),
   zero otherwise.  The declarator is constructed as an ARRAY_REF
   (to be decoded by grokdeclarator), whose operand 0 is what's on the
   left of the [] (filled by in set_array_declarator_type) and operand 1
   is the expression inside; whose TREE_TYPE is the type qualifiers and
   which has TREE_STATIC set if "static" is used.  */

tree
build_array_declarator (expr, quals, static_p, vla_unspec_p)
     tree expr;
     tree quals;
     int static_p;
     int vla_unspec_p;
{
  tree decl;
  decl = build_nt (ARRAY_REF, NULL_TREE, expr);
  TREE_TYPE (decl) = quals;
  TREE_STATIC (decl) = (static_p ? 1 : 0);
  if (pedantic && !flag_isoc99)
    {
      if (static_p || quals != NULL_TREE)
        pedwarn ("ISO C90 does not support `static' or type qualifiers in parameter array declarators");
      if (vla_unspec_p)
        pedwarn ("ISO C90 does not support `[*]' array declarators");
    }
  if (vla_unspec_p)
    warning ("GCC does not yet properly implement `[*]' array declarators");
  return decl;
}

/* Set the type of an array declarator.  DECL is the declarator, as
   constructed by build_array_declarator; TYPE is what appears on the left
   of the [] and goes in operand 0.  ABSTRACT_P is nonzero if it is an
   abstract declarator, zero otherwise; this is used to reject static and
   type qualifiers in abstract declarators, where they are not in the
   C99 grammar.  */

tree
set_array_declarator_type (decl, type, abstract_p)
     tree decl;
     tree type;
     int abstract_p;
{
  TREE_OPERAND (decl, 0) = type;
  if (abstract_p && (TREE_TYPE (decl) != NULL_TREE || TREE_STATIC (decl)))
    error ("static or type qualifiers in abstract declarator");
  return decl;
}
\f
/* Decode a "typename", such as "int **", returning a ..._TYPE node.  */

tree
groktypename (typename)
     tree typename;
{
  tree specs, attrs;

  if (TREE_CODE (typename) != TREE_LIST)
    return typename;

  split_specs_attrs (TREE_PURPOSE (typename), &specs, &attrs);

  typename = grokdeclarator (TREE_VALUE (typename), specs, TYPENAME, 0);

  /* Apply attributes.  */
  decl_attributes (&typename, attrs, 0);

  return typename;
}

/* Return a PARM_DECL node for a given pair of specs and declarator.  */

tree
groktypename_in_parm_context (typename)
     tree typename;
{
  if (TREE_CODE (typename) != TREE_LIST)
    return typename;
  return grokdeclarator (TREE_VALUE (typename),
                         TREE_PURPOSE (typename),
                         PARM, 0);
}

/* Decode a declarator in an ordinary declaration or data definition.
   This is called as soon as the type information and variable name
   have been parsed, before parsing the initializer if any.
   Here we create the ..._DECL node, fill in its type,
   and put it on the list of decls for the current context.
   The ..._DECL node is returned as the value.

   Exception: for arrays where the length is not specified,
   the type is left null, to be filled in by `finish_decl'.

   Function definitions do not come here; they go to start_function
   instead.  However, external and forward declarations of functions
   do go through here.  Structure field declarations are done by
   grokfield and not through here.  */

tree
start_decl (declarator, declspecs, initialized, attributes)
     tree declarator, declspecs;
     int initialized;
     tree attributes;
{
  tree decl;
  tree tem;
  
  /* An object declared as __attribute__((deprecated)) suppresses
     warnings of uses of other deprecated items.  */
  if (lookup_attribute ("deprecated", attributes))
    deprecated_state = DEPRECATED_SUPPRESS;

  decl = grokdeclarator (declarator, declspecs,
                         NORMAL, initialized);
  
  deprecated_state = DEPRECATED_NORMAL;

  if (warn_main > 0 && TREE_CODE (decl) != FUNCTION_DECL
      && MAIN_NAME_P (DECL_NAME (decl)))
    warning_with_decl (decl, "`%s' is usually a function");

  if (initialized)
    /* Is it valid for this decl to have an initializer at all?
       If not, set INITIALIZED to zero, which will indirectly
       tell `finish_decl' to ignore the initializer once it is parsed.  */
    switch (TREE_CODE (decl))
      {
      case TYPE_DECL:
        error ("typedef `%s' is initialized (use __typeof__ instead)",
               IDENTIFIER_POINTER (DECL_NAME (decl)));
        initialized = 0;
        break;

      case FUNCTION_DECL:
        error ("function `%s' is initialized like a variable",
               IDENTIFIER_POINTER (DECL_NAME (decl)));
        initialized = 0;
        break;

      case PARM_DECL:
        /* DECL_INITIAL in a PARM_DECL is really DECL_ARG_TYPE.  */
        error ("parameter `%s' is initialized",
               IDENTIFIER_POINTER (DECL_NAME (decl)));
        initialized = 0;
        break;

      default:
        /* Don't allow initializations for incomplete types
           except for arrays which might be completed by the initialization.  */

        /* This can happen if the array size is an undefined macro.  We already
           gave a warning, so we don't need another one.  */
        if (TREE_TYPE (decl) == error_mark_node)
          initialized = 0;
        else if (COMPLETE_TYPE_P (TREE_TYPE (decl)))
          {
            /* A complete type is ok if size is fixed.  */

            if (TREE_CODE (TYPE_SIZE (TREE_TYPE (decl))) != INTEGER_CST
                || C_DECL_VARIABLE_SIZE (decl))
              {
                error ("variable-sized object may not be initialized");
                initialized = 0;
              }
          }
        else if (TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE)
          {
            error ("variable `%s' has initializer but incomplete type",
                   IDENTIFIER_POINTER (DECL_NAME (decl)));
            initialized = 0;
          }
        else if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
          {
            error ("elements of array `%s' have incomplete type",
                   IDENTIFIER_POINTER (DECL_NAME (decl)));
            initialized = 0;
          }
      }

  if (initialized)
    {
#if 0
      /* Seems redundant with grokdeclarator.  */
      if (current_binding_level != global_binding_level
          && DECL_EXTERNAL (decl)
          && TREE_CODE (decl) != FUNCTION_DECL)
        warning ("declaration of `%s' has `extern' and is initialized",
                 IDENTIFIER_POINTER (DECL_NAME (decl)));
#endif
      DECL_EXTERNAL (decl) = 0;
      if (current_binding_level == global_binding_level)
        TREE_STATIC (decl) = 1;

      /* Tell `pushdecl' this is an initialized decl
         even though we don't yet have the initializer expression.
         Also tell `finish_decl' it may store the real initializer.  */
      DECL_INITIAL (decl) = error_mark_node;
    }

  /* If this is a function declaration, write a record describing it to the
     prototypes file (if requested).  */

  if (TREE_CODE (decl) == FUNCTION_DECL)
    gen_aux_info_record (decl, 0, 0, TYPE_ARG_TYPES (TREE_TYPE (decl)) != 0);

  /* ANSI specifies that a tentative definition which is not merged with
     a non-tentative definition behaves exactly like a definition with an
     initializer equal to zero.  (Section 3.7.2)

     -fno-common gives strict ANSI behavior, though this tends to break
     a large body of code that grew up without this rule.

     Thread-local variables are never common, since there's no entrenched
     body of code to break, and it allows more efficient variable references
     in the presence of dynamic linking.  */

  if (TREE_CODE (decl) == VAR_DECL
      && !initialized
      && TREE_PUBLIC (decl)
      && !DECL_THREAD_LOCAL (decl)
      && !flag_no_common)
    DECL_COMMON (decl) = 1;

  /* Set attributes here so if duplicate decl, will have proper attributes.  */
  decl_attributes (&decl, attributes, 0);

  /* If #pragma weak was used, mark the decl weak now.  */
  if (current_binding_level == global_binding_level)
    maybe_apply_pragma_weak (decl);

  if (TREE_CODE (decl) == FUNCTION_DECL
      && DECL_DECLARED_INLINE_P (decl)
      && DECL_UNINLINABLE (decl)
      && lookup_attribute ("noinline", DECL_ATTRIBUTES (decl)))
    warning_with_decl (decl,
                       "inline function `%s' given attribute noinline");

  /* Add this decl to the current binding level.
     TEM may equal DECL or it may be a previous decl of the same name.  */
  tem = pushdecl (decl);

  /* For a local variable, define the RTL now.  */
  if (current_binding_level != global_binding_level
      /* But not if this is a duplicate decl
         and we preserved the rtl from the previous one
         (which may or may not happen).  */
      && !DECL_RTL_SET_P (tem)
      && !DECL_CONTEXT (tem))
    {
      if (TREE_TYPE (tem) != error_mark_node
          && COMPLETE_TYPE_P (TREE_TYPE (tem)))
        expand_decl (tem);
      else if (TREE_CODE (TREE_TYPE (tem)) == ARRAY_TYPE
               && DECL_INITIAL (tem) != 0)
        expand_decl (tem);
    }

  return tem;
}

/* Finish processing of a declaration;
   install its initial value.
   If the length of an array type is not known before,
   it must be determined now, from the initial value, or it is an error.  */

void
finish_decl (decl, init, asmspec_tree)
     tree decl, init;
     tree asmspec_tree;
{
  tree type = TREE_TYPE (decl);
  int was_incomplete = (DECL_SIZE (decl) == 0);
  const char *asmspec = 0;

  /* If a name was specified, get the string.  */
  if (current_binding_level == global_binding_level)
    asmspec_tree = maybe_apply_renaming_pragma (decl, asmspec_tree);
  if (asmspec_tree)
    asmspec = TREE_STRING_POINTER (asmspec_tree);

  /* If `start_decl' didn't like having an initialization, ignore it now.  */
  if (init != 0 && DECL_INITIAL (decl) == 0)
    init = 0;
  
  /* Don't crash if parm is initialized.  */
  if (TREE_CODE (decl) == PARM_DECL)
    init = 0;

  if (init)
    store_init_value (decl, init);

  /* Deduce size of array from initialization, if not already known */
  if (TREE_CODE (type) == ARRAY_TYPE
      && TYPE_DOMAIN (type) == 0
      && TREE_CODE (decl) != TYPE_DECL)
    {
      int do_default
        = (TREE_STATIC (decl)
           /* Even if pedantic, an external linkage array
              may have incomplete type at first.  */
           ? pedantic && !TREE_PUBLIC (decl)
           : !DECL_EXTERNAL (decl));
      int failure
        = complete_array_type (type, DECL_INITIAL (decl), do_default);

      /* Get the completed type made by complete_array_type.  */
      type = TREE_TYPE (decl);

      if (failure == 1)
        error_with_decl (decl, "initializer fails to determine size of `%s'");

      else if (failure == 2)
        {
          if (do_default)
            error_with_decl (decl, "array size missing in `%s'");
          /* If a `static' var's size isn't known,
             make it extern as well as static, so it does not get
             allocated.
             If it is not `static', then do not mark extern;
             finish_incomplete_decl will give it a default size
             and it will get allocated.  */
          else if (!pedantic && TREE_STATIC (decl) && ! TREE_PUBLIC (decl))
            DECL_EXTERNAL (decl) = 1;
        }

      /* TYPE_MAX_VALUE is always one less than the number of elements
         in the array, because we start counting at zero.  Therefore,
         warn only if the value is less than zero.  */
      else if (pedantic && TYPE_DOMAIN (type) != 0
              && tree_int_cst_sgn (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) < 0)
        error_with_decl (decl, "zero or negative size array `%s'");

      layout_decl (decl, 0);
    }

  if (TREE_CODE (decl) == VAR_DECL)
    {
      if (DECL_SIZE (decl) == 0 && TREE_TYPE (decl) != error_mark_node
          && COMPLETE_TYPE_P (TREE_TYPE (decl)))
        layout_decl (decl, 0);

      if (DECL_SIZE (decl) == 0
          /* Don't give an error if we already gave one earlier.  */
          && TREE_TYPE (decl) != error_mark_node
          && (TREE_STATIC (decl)
              ?
                /* A static variable with an incomplete type
                   is an error if it is initialized.
                   Also if it is not file scope.
                   Otherwise, let it through, but if it is not `extern'
                   then it may cause an error message later.  */
                (DECL_INITIAL (decl) != 0
                 || DECL_CONTEXT (decl) != 0)
              :
                /* An automatic variable with an incomplete type
                   is an error.  */
                !DECL_EXTERNAL (decl)))
        {
          error_with_decl (decl, "storage size of `%s' isn't known");
          TREE_TYPE (decl) = error_mark_node;
        }

      if ((DECL_EXTERNAL (decl) || TREE_STATIC (decl))
          && DECL_SIZE (decl) != 0)
        {
          if (TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST)
            constant_expression_warning (DECL_SIZE (decl));
          else
            error_with_decl (decl, "storage size of `%s' isn't constant");
        }

      if (TREE_USED (type))
        TREE_USED (decl) = 1;
    }

  /* If this is a function and an assembler name is specified, reset DECL_RTL
     so we can give it its new name.  Also, update built_in_decls if it
     was a normal built-in.  */
  if (TREE_CODE (decl) == FUNCTION_DECL && asmspec)
    {
      if (DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
        {
          tree builtin = built_in_decls [DECL_FUNCTION_CODE (decl)];
          SET_DECL_RTL (builtin, NULL_RTX);
          SET_DECL_ASSEMBLER_NAME (builtin, get_identifier (asmspec));
#ifdef TARGET_MEM_FUNCTIONS
          if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMCPY)
            init_block_move_fn (asmspec);
          else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_MEMSET)
            init_block_clear_fn (asmspec);
#else
          if (DECL_FUNCTION_CODE (decl) == BUILT_IN_BCOPY)
            init_block_move_fn (asmspec);
          else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_BZERO)
            init_block_clear_fn (asmspec);
#endif
        }
      SET_DECL_RTL (decl, NULL_RTX);
      SET_DECL_ASSEMBLER_NAME (decl, get_identifier (asmspec));
    }

  /* Output the assembler code and/or RTL code for variables and functions,
     unless the type is an undefined structure or union.
     If not, it will get done when the type is completed.  */

  if (TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == FUNCTION_DECL)
    {
      /* This is a no-op in c-lang.c or something real in objc-act.c.  */
      if (flag_objc)
        objc_check_decl (decl);

      if (!DECL_CONTEXT (decl))
        {
          if (DECL_INITIAL (decl) == NULL_TREE
              || DECL_INITIAL (decl) == error_mark_node)
            /* Don't output anything
               when a tentative file-scope definition is seen.
               But at end of compilation, do output code for them.  */
            DECL_DEFER_OUTPUT (decl) = 1;
          rest_of_decl_compilation (decl, asmspec,
                                    (DECL_CONTEXT (decl) == 0
                                     || TREE_ASM_WRITTEN (decl)), 0);
        }
      else
        {
          /* This is a local variable.  If there is an ASMSPEC, the
             user has requested that we handle it specially.  */
          if (asmspec)
            {
              /* In conjunction with an ASMSPEC, the `register'
                 keyword indicates that we should place the variable
                 in a particular register.  */
              if (DECL_REGISTER (decl))
                DECL_C_HARD_REGISTER (decl) = 1;

              /* If this is not a static variable, issue a warning.
                 It doesn't make any sense to give an ASMSPEC for an
                 ordinary, non-register local variable.  Historically,
                 GCC has accepted -- but ignored -- the ASMSPEC in
                 this case.  */
              if (TREE_CODE (decl) == VAR_DECL 
                  && !DECL_REGISTER (decl)
                  && !TREE_STATIC (decl))
                warning_with_decl (decl,
                                   "ignoring asm-specifier for non-static local variable `%s'");
              else
                SET_DECL_ASSEMBLER_NAME (decl, get_identifier (asmspec));
            }

          if (TREE_CODE (decl) != FUNCTION_DECL)
            add_decl_stmt (decl);
        }

      if (DECL_CONTEXT (decl) != 0)
        {
          /* Recompute the RTL of a local array now
             if it used to be an incomplete type.  */
          if (was_incomplete
              && ! TREE_STATIC (decl) && ! DECL_EXTERNAL (decl))
            {
              /* If we used it already as memory, it must stay in memory.  */
              TREE_ADDRESSABLE (decl) = TREE_USED (decl);
              /* If it's still incomplete now, no init will save it.  */
              if (DECL_SIZE (decl) == 0)
                DECL_INITIAL (decl) = 0;
            }
        }
    }

  if (TREE_CODE (decl) == TYPE_DECL)
    {
      /* This is a no-op in c-lang.c or something real in objc-act.c.  */
      if (flag_objc)
        objc_check_decl (decl);
      rest_of_decl_compilation (decl, NULL, DECL_CONTEXT (decl) == 0, 0);
    }

  /* At the end of a declaration, throw away any variable type sizes
     of types defined inside that declaration.  There is no use
     computing them in the following function definition.  */
  if (current_binding_level == global_binding_level)
    get_pending_sizes ();
}

/* Given a parsed parameter declaration,
   decode it into a PARM_DECL and push that on the current binding level.
   Also, for the sake of forward parm decls,
   record the given order of parms in `parm_order'.  */

void
push_parm_decl (parm)
     tree parm;
{
  tree decl;
  int old_immediate_size_expand = immediate_size_expand;
  /* Don't try computing parm sizes now -- wait till fn is called.  */
  immediate_size_expand = 0;

  decl = grokdeclarator (TREE_VALUE (TREE_PURPOSE (parm)),
                         TREE_PURPOSE (TREE_PURPOSE (parm)), PARM, 0);
  decl_attributes (&decl, TREE_VALUE (parm), 0);

#if 0
  if (DECL_NAME (decl))
    {
      tree olddecl;
      olddecl = lookup_name (DECL_NAME (decl));
      if (pedantic && olddecl != 0 && TREE_CODE (olddecl) == TYPE_DECL)
        pedwarn_with_decl (decl,
                           "ISO C forbids parameter `%s' shadowing typedef");
    }
#endif

  decl = pushdecl (decl);

  immediate_size_expand = old_immediate_size_expand;

  current_binding_level->parm_order
    = tree_cons (NULL_TREE, decl, current_binding_level->parm_order);

  /* Add this decl to the current binding level.  */
  finish_decl (decl, NULL_TREE, NULL_TREE);
}

/* Clear the given order of parms in `parm_order'.
   Used at start of parm list,
   and also at semicolon terminating forward decls.  */

void
clear_parm_order ()
{
  current_binding_level->parm_order = NULL_TREE;
}
\f
static GTY(()) int compound_literal_number;

/* Build a COMPOUND_LITERAL_EXPR.  TYPE is the type given in the compound
   literal, which may be an incomplete array type completed by the
   initializer; INIT is a CONSTRUCTOR that initializes the compound
   literal.  */

tree
build_compound_literal (type, init)
     tree type;
     tree init;
{
  /* We do not use start_decl here because we have a type, not a declarator;
     and do not use finish_decl because the decl should be stored inside
     the COMPOUND_LITERAL_EXPR rather than added elsewhere as a DECL_STMT.  */
  tree decl = build_decl (VAR_DECL, NULL_TREE, type);
  tree complit;
  tree stmt;
  DECL_EXTERNAL (decl) = 0;
  TREE_PUBLIC (decl) = 0;
  TREE_STATIC (decl) = (current_binding_level == global_binding_level);
  DECL_CONTEXT (decl) = current_function_decl;
  TREE_USED (decl) = 1;
  TREE_TYPE (decl) = type;
  TREE_READONLY (decl) = TREE_READONLY (type);
  store_init_value (decl, init);

  if (TREE_CODE (type) == ARRAY_TYPE && !COMPLETE_TYPE_P (type))
    {
      int failure = complete_array_type (type, DECL_INITIAL (decl), 1);
      if (failure)
        abort ();
    }

  type = TREE_TYPE (decl);
  if (type == error_mark_node || !COMPLETE_TYPE_P (type))
    return error_mark_node;

  stmt = build_stmt (DECL_STMT, decl);
  complit = build1 (COMPOUND_LITERAL_EXPR, TREE_TYPE (decl), stmt);
  TREE_SIDE_EFFECTS (complit) = 1;

  layout_decl (decl, 0);

  if (TREE_STATIC (decl))
    {
      /* This decl needs a name for the assembler output.  We also need
         a unique suffix to be added to the name.  */
      char *name;

      ASM_FORMAT_PRIVATE_NAME (name, "__compound_literal", 
                               compound_literal_number);
      compound_literal_number++;
      DECL_NAME (decl) = get_identifier (name);
      DECL_DEFER_OUTPUT (decl) = 1;
      DECL_COMDAT (decl) = 1;
      DECL_ARTIFICIAL (decl) = 1;
      pushdecl (decl);
      rest_of_decl_compilation (decl, NULL, 1, 0);
    }

  return complit;
}
\f
/* Make TYPE a complete type based on INITIAL_VALUE.
   Return 0 if successful, 1 if INITIAL_VALUE can't be deciphered,
   2 if there was no information (in which case assume 1 if DO_DEFAULT).  */

int
complete_array_type (type, initial_value, do_default)
     tree type;
     tree initial_value;
     int do_default;
{
  tree maxindex = NULL_TREE;
  int value = 0;

  if (initial_value)
    {
      /* Note MAXINDEX  is really the maximum index,
         one less than the size.  */
      if (TREE_CODE (initial_value) == STRING_CST)
        {
          int eltsize
            = int_size_in_bytes (TREE_TYPE (TREE_TYPE (initial_value)));
          maxindex = build_int_2 ((TREE_STRING_LENGTH (initial_value)
                                   / eltsize) - 1, 0);
        }
      else if (TREE_CODE (initial_value) == CONSTRUCTOR)
        {
          tree elts = CONSTRUCTOR_ELTS (initial_value);
          maxindex = build_int_2 (-1, -1);
          for (; elts; elts = TREE_CHAIN (elts))
            {
              if (TREE_PURPOSE (elts))
                maxindex = TREE_PURPOSE (elts);
              else
                maxindex = fold (build (PLUS_EXPR, integer_type_node,
                                        maxindex, integer_one_node));
            }
          maxindex = copy_node (maxindex);
        }
      else
        {
          /* Make an error message unless that happened already.  */
          if (initial_value != error_mark_node)
            value = 1;

          /* Prevent further error messages.  */
          maxindex = build_int_2 (0, 0);
        }
    }

  if (!maxindex)
    {
      if (do_default)
        maxindex = build_int_2 (0, 0);
      value = 2;
    }

  if (maxindex)
    {
      TYPE_DOMAIN (type) = build_index_type (maxindex);
      if (!TREE_TYPE (maxindex))
        TREE_TYPE (maxindex) = TYPE_DOMAIN (type);
    }

  /* Lay out the type now that we can get the real answer.  */

  layout_type (type);

  return value;
}
\f
/* Determine whether TYPE is a structure with a flexible array member,
   or a union containing such a structure (possibly recursively).  */

static bool
flexible_array_type_p (type)
     tree type;
{
  tree x;
  switch (TREE_CODE (type))
    {
    case RECORD_TYPE:
      x = TYPE_FIELDS (type);
      if (x == NULL_TREE)
        return false;
      while (TREE_CHAIN (x) != NULL_TREE)
        x = TREE_CHAIN (x);
      if (TREE_CODE (TREE_TYPE (x)) == ARRAY_TYPE
          && TYPE_SIZE (TREE_TYPE (x)) == NULL_TREE
          && TYPE_DOMAIN (TREE_TYPE (x)) != NULL_TREE
          && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (x))) == NULL_TREE)
        return true;
      return false;
    case UNION_TYPE:
      for (x = TYPE_FIELDS (type); x != NULL_TREE; x = TREE_CHAIN (x))
        {
          if (flexible_array_type_p (TREE_TYPE (x)))
            return true;
        }
      return false;
    default:
    return false;
  }
}
\f
/* Given declspecs and a declarator,
   determine the name and type of the object declared
   and construct a ..._DECL node for it.
   (In one case we can return a ..._TYPE node instead.
    For invalid input we sometimes return 0.)

   DECLSPECS is a chain of tree_list nodes whose value fields
    are the storage classes and type specifiers.

   DECL_CONTEXT says which syntactic context this declaration is in:
     NORMAL for most contexts.  Make a VAR_DECL or FUNCTION_DECL or TYPE_DECL.
     FUNCDEF for a function definition.  Like NORMAL but a few different
      error messages in each case.  Return value may be zero meaning
      this definition is too screwy to try to parse.
     PARM for a parameter declaration (either within a function prototype
      or before a function body).  Make a PARM_DECL, or return void_type_node.
     TYPENAME if for a typename (in a cast or sizeof).
      Don't make a DECL node; just return the ..._TYPE node.
     FIELD for a struct or union field; make a FIELD_DECL.
     BITFIELD for a field with specified width.
   INITIALIZED is 1 if the decl has an initializer.

   In the TYPENAME case, DECLARATOR is really an absolute declarator.
   It may also be so in the PARM case, for a prototype where the
   argument type is specified but not the name.

   This function is where the complicated C meanings of `static'
   and `extern' are interpreted.  */

static tree
grokdeclarator (declarator, declspecs, decl_context, initialized)
     tree declspecs;
     tree declarator;
     enum decl_context decl_context;
     int initialized;
{
  int specbits = 0;
  tree spec;
  tree type = NULL_TREE;
  int longlong = 0;
  int constp;
  int restrictp;
  int volatilep;
  int type_quals = TYPE_UNQUALIFIED;
  int inlinep;
  int explicit_int = 0;
  int explicit_char = 0;
  int defaulted_int = 0;
  tree typedef_decl = 0;
  const char *name;
  tree typedef_type = 0;
  int funcdef_flag = 0;
  enum tree_code innermost_code = ERROR_MARK;
  int bitfield = 0;
  int size_varies = 0;
  tree decl_attr = NULL_TREE;
  tree array_ptr_quals = NULL_TREE;
  int array_parm_static = 0;
  tree returned_attrs = NULL_TREE;

  if (decl_context == BITFIELD)
    bitfield = 1, decl_context = FIELD;

  if (decl_context == FUNCDEF)
    funcdef_flag = 1, decl_context = NORMAL;

  /* Look inside a declarator for the name being declared
     and get it as a string, for an error message.  */
  {
    tree decl = declarator;
    name = 0;

    while (decl)
      switch (TREE_CODE (decl))
        {
        case ARRAY_REF:
        case INDIRECT_REF:
        case CALL_EXPR:
          innermost_code = TREE_CODE (decl);
          decl = TREE_OPERAND (decl, 0);
          break;

        case TREE_LIST:
          decl = TREE_VALUE (decl);
          break;

        case IDENTIFIER_NODE:
          name = IDENTIFIER_POINTER (decl);
          decl = 0;
          break;

        default:
          abort ();
        }
    if (name == 0)
      name = "type name";
  }

  /* A function definition's declarator must have the form of
     a function declarator.  */

  if (funcdef_flag && innermost_code != CALL_EXPR)
    return 0;

  /* Anything declared one level down from the top level
     must be one of the parameters of a function
     (because the body is at least two levels down).  */

  /* If this looks like a function definition, make it one,
     even if it occurs where parms are expected.
     Then store_parm_decls will reject it and not use it as a parm.  */
  if (decl_context == NORMAL && !funcdef_flag
      && current_binding_level->parm_flag)
    decl_context = PARM;

  /* Look through the decl specs and record which ones appear.
     Some typespecs are defined as built-in typenames.
     Others, the ones that are modifiers of other types,
     are represented by bits in SPECBITS: set the bits for
     the modifiers that appear.  Storage class keywords are also in SPECBITS.

     If there is a typedef name or a type, store the type in TYPE.
     This includes builtin typedefs such as `int'.

     Set EXPLICIT_INT or EXPLICIT_CHAR if the type is `int' or `char'
     and did not come from a user typedef.

     Set LONGLONG if `long' is mentioned twice.  */

  for (spec = declspecs; spec; spec = TREE_CHAIN (spec))
    {
      tree id = TREE_VALUE (spec);

      /* If the entire declaration is itself tagged as deprecated then
         suppress reports of deprecated items.  */
      if (id && TREE_DEPRECATED (id))
        {
          if (deprecated_state != DEPRECATED_SUPPRESS)
            warn_deprecated_use (id);
        }

      if (id == ridpointers[(int) RID_INT])
        explicit_int = 1;
      if (id == ridpointers[(int) RID_CHAR])
        explicit_char = 1;

      if (TREE_CODE (id) == IDENTIFIER_NODE && C_IS_RESERVED_WORD (id))
        {
          enum rid i = C_RID_CODE (id);
          if ((int) i <= (int) RID_LAST_MODIFIER)
            {
              if (i == RID_LONG && (specbits & (1 << (int) RID_LONG)))
                {
                  if (longlong)
                    error ("`long long long' is too long for GCC");
                  else
                    {
                      if (pedantic && !flag_isoc99 && ! in_system_header
                          && warn_long_long)
                        pedwarn ("ISO C90 does not support `long long'");
                      longlong = 1;
                    }
                }
              else if (specbits & (1 << (int) i))
                {
                  if (i == RID_CONST || i == RID_VOLATILE || i == RID_RESTRICT)
                    {
                      if (!flag_isoc99)
                        pedwarn ("duplicate `%s'", IDENTIFIER_POINTER (id));
                    }
                  else
                    error ("duplicate `%s'", IDENTIFIER_POINTER (id));
                }

              /* Diagnose "__thread extern".  Recall that this list
                 is in the reverse order seen in the text.  */
              if (i == RID_THREAD
                  && (specbits & (1 << (int) RID_EXTERN
                                  | 1 << (int) RID_STATIC)))
                {
                  if (specbits & 1 << (int) RID_EXTERN)
                    error ("`__thread' before `extern'");
                  else
                    error ("`__thread' before `static'");
                }

              specbits |= 1 << (int) i;
              goto found;
            }
        }
      if (type)
        error ("two or more data types in declaration of `%s'", name);
      /* Actual typedefs come to us as TYPE_DECL nodes.  */
      else if (TREE_CODE (id) == TYPE_DECL)
        {
          if (TREE_TYPE (id) == error_mark_node)
            ; /* Allow the type to default to int to avoid cascading errors.  */
          else
            {
              type = TREE_TYPE (id);
              decl_attr = DECL_ATTRIBUTES (id);
              typedef_decl = id;
            }
        }
      /* Built-in types come as identifiers.  */
      else if (TREE_CODE (id) == IDENTIFIER_NODE)
        {
          tree t = lookup_name (id);
          if (TREE_TYPE (t) == error_mark_node)
            ;
          else if (!t || TREE_CODE (t) != TYPE_DECL)
            error ("`%s' fails to be a typedef or built in type",
                   IDENTIFIER_POINTER (id));
          else
            {
              type = TREE_TYPE (t);
              typedef_decl = t;
            }
        }
      else if (TREE_CODE (id) != ERROR_MARK)
        type = id;

    found:
      ;
    }

  typedef_type = type;
  if (type)
    size_varies = C_TYPE_VARIABLE_SIZE (type);

  /* No type at all: default to `int', and set DEFAULTED_INT
     because it was not a user-defined typedef.  */

  if (type == 0)
    {
      if ((! (specbits & ((1 << (int) RID_LONG) | (1 << (int) RID_SHORT)
                          | (1 << (int) RID_SIGNED)
                          | (1 << (int) RID_UNSIGNED)
                          | (1 << (int) RID_COMPLEX))))
          /* Don't warn about typedef foo = bar.  */
          && ! (specbits & (1 << (int) RID_TYPEDEF) && initialized)
          && ! in_system_header)
        {
          /* Issue a warning if this is an ISO C 99 program or if -Wreturn-type
             and this is a function, or if -Wimplicit; prefer the former
             warning since it is more explicit.  */
          if ((warn_implicit_int || warn_return_type || flag_isoc99)
              && funcdef_flag)
            warn_about_return_type = 1;
          else if (warn_implicit_int || flag_isoc99)
            pedwarn_c99 ("type defaults to `int' in declaration of `%s'",
                         name);
        }

      defaulted_int = 1;
      type = integer_type_node;
    }

  /* Now process the modifiers that were specified
     and check for invalid combinations.  */

  /* Long double is a special combination.  */

  if ((specbits & 1 << (int) RID_LONG) && ! longlong
      && TYPE_MAIN_VARIANT (type) == double_type_node)
    {
      specbits &= ~(1 << (int) RID_LONG);
      type = long_double_type_node;
    }

  /* Check all other uses of type modifiers.  */

  if (specbits & ((1 << (int) RID_LONG) | (1 << (int) RID_SHORT)
                  | (1 << (int) RID_UNSIGNED) | (1 << (int) RID_SIGNED)))
    {
      int ok = 0;

      if ((specbits & 1 << (int) RID_LONG)
          && (specbits & 1 << (int) RID_SHORT))
        error ("both long and short specified for `%s'", name);
      else if (((specbits & 1 << (int) RID_LONG)
                || (specbits & 1 << (int) RID_SHORT))
               && explicit_char)
        error ("long or short specified with char for `%s'", name);
      else if (((specbits & 1 << (int) RID_LONG)
                || (specbits & 1 << (int) RID_SHORT))
               && TREE_CODE (type) == REAL_TYPE)
        {
          static int already = 0;

          error ("long or short specified with floating type for `%s'", name);
          if (! already && ! pedantic)
            {
              error ("the only valid combination is `long double'");
              already = 1;
            }
        }
      else if ((specbits & 1 << (int) RID_SIGNED)
               && (specbits & 1 << (int) RID_UNSIGNED))
        error ("both signed and unsigned specified for `%s'", name);
      else if (TREE_CODE (type) != INTEGER_TYPE)
        error ("long, short, signed or unsigned invalid for `%s'", name);
      else
        {
          ok = 1;
          if (!explicit_int && !defaulted_int && !explicit_char)
            {
              error ("long, short, signed or unsigned used invalidly for `%s'",
                     name);
              ok = 0;
            }
        }

      /* Discard the type modifiers if they are invalid.  */
      if (! ok)
        {
          specbits &= ~((1 << (int) RID_LONG) | (1 << (int) RID_SHORT)
                        | (1 << (int) RID_UNSIGNED) | (1 << (int) RID_SIGNED));
          longlong = 0;
        }
    }

  if ((specbits & (1 << (int) RID_COMPLEX))
      && TREE_CODE (type) != INTEGER_TYPE && TREE_CODE (type) != REAL_TYPE)
    {
      error ("complex invalid for `%s'", name);
      specbits &= ~(1 << (int) RID_COMPLEX);
    }

  /* Decide whether an integer type is signed or not.
     Optionally treat bitfields as signed by default.  */
  if (specbits & 1 << (int) RID_UNSIGNED
      || (bitfield && ! flag_signed_bitfields
          && (explicit_int || defaulted_int || explicit_char
              /* A typedef for plain `int' without `signed'
                 can be controlled just like plain `int'.  */
              || ! (typedef_decl != 0
                    && C_TYPEDEF_EXPLICITLY_SIGNED (typedef_decl)))
          && TREE_CODE (type) != ENUMERAL_TYPE
          && !(specbits & 1 << (int) RID_SIGNED)))
    {
      if (longlong)
        type = long_long_unsigned_type_node;
      else if (specbits & 1 << (int) RID_LONG)
        type = long_unsigned_type_node;
      else if (specbits & 1 << (int) RID_SHORT)
        type = short_unsigned_type_node;
      else if (type == char_type_node)
        type = unsigned_char_type_node;
      else if (typedef_decl)
        type = c_common_unsigned_type (type);
      else
        type = unsigned_type_node;
    }
  else if ((specbits & 1 << (int) RID_SIGNED)
           && type == char_type_node)
    type = signed_char_type_node;
  else if (longlong)
    type = long_long_integer_type_node;
  else if (specbits & 1 << (int) RID_LONG)
    type = long_integer_type_node;
  else if (specbits & 1 << (int) RID_SHORT)
    type = short_integer_type_node;

  if (specbits & 1 << (int) RID_COMPLEX)
    {
      if (pedantic && !flag_isoc99)
        pedwarn ("ISO C90 does not support complex types");
      /* If we just have "complex", it is equivalent to
         "complex double", but if any modifiers at all are specified it is
         the complex form of TYPE.  E.g, "complex short" is
         "complex short int".  */

      if (defaulted_int && ! longlong
          && ! (specbits & ((1 << (int) RID_LONG) | (1 << (int) RID_SHORT)
                            | (1 << (int) RID_SIGNED)
                            | (1 << (int) RID_UNSIGNED))))
        {
          if (pedantic)
            pedwarn ("ISO C does not support plain `complex' meaning `double complex'");
          type = complex_double_type_node;
        }
      else if (type == integer_type_node)
        {
          if (pedantic)
            pedwarn ("ISO C does not support complex integer types");
          type = complex_integer_type_node;
        }
      else if (type == float_type_node)
        type = complex_float_type_node;
      else if (type == double_type_node)
        type = complex_double_type_node;
      else if (type == long_double_type_node)
        type = complex_long_double_type_node;
      else
        {
          if (pedantic)
            pedwarn ("ISO C does not support complex integer types");
          type = build_complex_type (type);
        }
    }

  /* Figure out the type qualifiers for the declaration.  There are
     two ways a declaration can become qualified.  One is something
     like `const int i' where the `const' is explicit.  Another is
     something like `typedef const int CI; CI i' where the type of the
     declaration contains the `const'.  */
  constp = !! (specbits & 1 << (int) RID_CONST) + TYPE_READONLY (type);
  restrictp = !! (specbits & 1 << (int) RID_RESTRICT) + TYPE_RESTRICT (type);
  volatilep = !! (specbits & 1 << (int) RID_VOLATILE) + TYPE_VOLATILE (type);
  inlinep = !! (specbits & (1 << (int) RID_INLINE));
  if (constp > 1 && ! flag_isoc99)
    pedwarn ("duplicate `const'");
  if (restrictp > 1 && ! flag_isoc99)
    pedwarn ("duplicate `restrict'");
  if (volatilep > 1 && ! flag_isoc99)
    pedwarn ("duplicate `volatile'");
  if (! flag_gen_aux_info && (TYPE_QUALS (type)))
    type = TYPE_MAIN_VARIANT (type);
  type_quals = ((constp ? TYPE_QUAL_CONST : 0)
                | (restrictp ? TYPE_QUAL_RESTRICT : 0)
                | (volatilep ? TYPE_QUAL_VOLATILE : 0));

  /* Warn if two storage classes are given. Default to `auto'.  */

  {
    int nclasses = 0;

    if (specbits & 1 << (int) RID_AUTO) nclasses++;
    if (specbits & 1 << (int) RID_STATIC) nclasses++;
    if (specbits & 1 << (int) RID_EXTERN) nclasses++;
    if (specbits & 1 << (int) RID_REGISTER) nclasses++;
    if (specbits & 1 << (int) RID_TYPEDEF) nclasses++;

    /* "static __thread" and "extern __thread" are allowed.  */
    if ((specbits & (1 << (int) RID_THREAD
                     | 1 << (int) RID_STATIC
                     | 1 << (int) RID_EXTERN)) == (1 << (int) RID_THREAD))
      nclasses++;

    /* Warn about storage classes that are invalid for certain
       kinds of declarations (parameters, typenames, etc.).  */

    if (nclasses > 1)
      error ("multiple storage classes in declaration of `%s'", name);
    else if (funcdef_flag
             && (specbits
                 & ((1 << (int) RID_REGISTER)
                    | (1 << (int) RID_AUTO)
                    | (1 << (int) RID_TYPEDEF)
                    | (1 << (int) RID_THREAD))))
      {
        if (specbits & 1 << (int) RID_AUTO
            && (pedantic || current_binding_level == global_binding_level))
          pedwarn ("function definition declared `auto'");
        if (specbits & 1 << (int) RID_REGISTER)
          error ("function definition declared `register'");
        if (specbits & 1 << (int) RID_TYPEDEF)
          error ("function definition declared `typedef'");
        if (specbits & 1 << (int) RID_THREAD)
          error ("function definition declared `__thread'");
        specbits &= ~((1 << (int) RID_TYPEDEF) | (1 << (int) RID_REGISTER)
                      | (1 << (int) RID_AUTO) | (1 << (int) RID_THREAD));
      }
    else if (decl_context != NORMAL && nclasses > 0)
      {
        if (decl_context == PARM && specbits & 1 << (int) RID_REGISTER)
          ;
        else
          {
            switch (decl_context)
              {
              case FIELD:
                error ("storage class specified for structure field `%s'",
                       name);
                break;
              case PARM:
                error ("storage class specified for parameter `%s'", name);
                break;
              default:
                error ("storage class specified for typename");
                break;
              }
            specbits &= ~((1 << (int) RID_TYPEDEF) | (1 << (int) RID_REGISTER)
                          | (1 << (int) RID_AUTO) | (1 << (int) RID_STATIC)
                          | (1 << (int) RID_EXTERN) | (1 << (int) RID_THREAD));
          }
      }
    else if (specbits & 1 << (int) RID_EXTERN && initialized && ! funcdef_flag)
      {
        /* `extern' with initialization is invalid if not at top level.  */
        if (current_binding_level == global_binding_level)
          warning ("`%s' initialized and declared `extern'", name);
        else
          error ("`%s' has both `extern' and initializer", name);
      }
    else if (current_binding_level == global_binding_level)
      {
        if (specbits & 1 << (int) RID_AUTO)
          error ("top-level declaration of `%s' specifies `auto'", name);
      }
    else
      {
        if (specbits & 1 << (int) RID_EXTERN && funcdef_flag)
          error ("nested function `%s' declared `extern'", name);
        else if ((specbits & (1 << (int) RID_THREAD
                               | 1 << (int) RID_EXTERN
                               | 1 << (int) RID_STATIC))
                 == (1 << (int) RID_THREAD))
          {
            error ("function-scope `%s' implicitly auto and declared `__thread'",
                   name);
            specbits &= ~(1 << (int) RID_THREAD);
          }
      }
  }

  /* Now figure out the structure of the declarator proper.
     Descend through it, creating more complex types, until we reach
     the declared identifier (or NULL_TREE, in an absolute declarator).  */

  while (declarator && TREE_CODE (declarator) != IDENTIFIER_NODE)
    {
      if (type == error_mark_node)
        {
          declarator = TREE_OPERAND (declarator, 0);
          continue;
        }

      /* Each level of DECLARATOR is either an ARRAY_REF (for ...[..]),
         an INDIRECT_REF (for *...),
         a CALL_EXPR (for ...(...)),
         a TREE_LIST (for nested attributes),
         an identifier (for the name being declared)
         or a null pointer (for the place in an absolute declarator
         where the name was omitted).
         For the last two cases, we have just exited the loop.

         At this point, TYPE is the type of elements of an array,
         or for a function to return, or for a pointer to point to.
         After this sequence of ifs, TYPE is the type of the
         array or function or pointer, and DECLARATOR has had its
         outermost layer removed.  */

      if (array_ptr_quals != NULL_TREE || array_parm_static)
        {
          /* Only the innermost declarator (making a parameter be of
             array type which is converted to pointer type)
             may have static or type qualifiers.  */
          error ("static or type qualifiers in non-parameter array declarator");
          array_ptr_quals = NULL_TREE;
          array_parm_static = 0;
        }

      if (TREE_CODE (declarator) == TREE_LIST)
        {
          /* We encode a declarator with embedded attributes using
             a TREE_LIST.  */
          tree attrs = TREE_PURPOSE (declarator);
          tree inner_decl;
          int attr_flags = 0;
          declarator = TREE_VALUE (declarator);
          inner_decl = declarator;
          while (inner_decl != NULL_TREE
                 && TREE_CODE (inner_decl) == TREE_LIST)
            inner_decl = TREE_VALUE (inner_decl);
          if (inner_decl == NULL_TREE
              || TREE_CODE (inner_decl) == IDENTIFIER_NODE)
            attr_flags |= (int) ATTR_FLAG_DECL_NEXT;
          else if (TREE_CODE (inner_decl) == CALL_EXPR)
            attr_flags |= (int) ATTR_FLAG_FUNCTION_NEXT;
          else if (TREE_CODE (inner_decl) == ARRAY_REF)
            attr_flags |= (int) ATTR_FLAG_ARRAY_NEXT;
          returned_attrs = decl_attributes (&type,
                                            chainon (returned_attrs, attrs),
                                            attr_flags);
        }
      else if (TREE_CODE (declarator) == ARRAY_REF)
        {
          tree itype = NULL_TREE;
          tree size = TREE_OPERAND (declarator, 1);
          /* The index is a signed object `sizetype' bits wide.  */
          tree index_type = c_common_signed_type (sizetype);

          array_ptr_quals = TREE_TYPE (declarator);
          array_parm_static = TREE_STATIC (declarator);

          declarator = TREE_OPERAND (declarator, 0);

          /* Check for some types that there cannot be arrays of.  */

          if (VOID_TYPE_P (type))
            {
              error ("declaration of `%s' as array of voids", name);
              type = error_mark_node;
            }

          if (TREE_CODE (type) == FUNCTION_TYPE)
            {
              error ("declaration of `%s' as array of functions", name);
              type = error_mark_node;
            }

          if (pedantic && flexible_array_type_p (type))
            pedwarn ("invalid use of structure with flexible array member");

          if (size == error_mark_node)
            type = error_mark_node;

          if (type == error_mark_node)
            continue;

          /* If size was specified, set ITYPE to a range-type for that size.
             Otherwise, ITYPE remains null.  finish_decl may figure it out
             from an initial value.  */

          if (size)
            {
              /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
              STRIP_TYPE_NOPS (size);

              if (! INTEGRAL_TYPE_P (TREE_TYPE (size)))
                {
                  error ("size of array `%s' has non-integer type", name);
                  size = integer_one_node;
                }

              if (pedantic && integer_zerop (size))
                pedwarn ("ISO C forbids zero-size array `%s'", name);

              if (TREE_CODE (size) == INTEGER_CST)
                {
                  constant_expression_warning (size);
                  if (tree_int_cst_sgn (size) < 0)
                    {
                      error ("size of array `%s' is negative", name);
                      size = integer_one_node;
                    }
                }
              else
                {
                  /* Make sure the array size remains visibly nonconstant
                     even if it is (eg) a const variable with known value.  */
                  size_varies = 1;

                  if (!flag_isoc99 && pedantic)
                    {
                      if (TREE_CONSTANT (size))
                        pedwarn ("ISO C90 forbids array `%s' whose size can't be evaluated",
                                 name);
                      else
                        pedwarn ("ISO C90 forbids variable-size array `%s'",
                                 name);
                    }
                }

              if (integer_zerop (size))
                {
                  /* A zero-length array cannot be represented with an
                     unsigned index type, which is what we'll get with
                     build_index_type.  Create an open-ended range instead.  */
                  itype = build_range_type (sizetype, size, NULL_TREE);
                }
              else
                {
                  /* Compute the maximum valid index, that is, size - 1.
                     Do the calculation in index_type, so that if it is
                     a variable the computations will be done in the
                     proper mode.  */
                  itype = fold (build (MINUS_EXPR, index_type,
                                       convert (index_type, size),
                                       convert (index_type, size_one_node)));

                  /* If that overflowed, the array is too big.
                     ??? While a size of INT_MAX+1 technically shouldn't
                     cause an overflow (because we subtract 1), the overflow
                     is recorded during the conversion to index_type, before
                     the subtraction.  Handling this case seems like an
                     unnecessary complication.  */
                  if (TREE_OVERFLOW (itype))
                    {
                      error ("size of array `%s' is too large", name);
                      type = error_mark_node;
                      continue;
                    }

                  if (size_varies)
                    {
                      /* We must be able to distinguish the
                         SAVE_EXPR_CONTEXT for the variably-sized type
                         so that we can set it correctly in
                         set_save_expr_context.  The convention is
                         that all SAVE_EXPRs that need to be reset
                         have NULL_TREE for their SAVE_EXPR_CONTEXT.  */
                      tree cfd = current_function_decl;
                      if (decl_context == PARM)
                        current_function_decl = NULL_TREE;
                      itype = variable_size (itype);
                      if (decl_context == PARM)
                        current_function_decl = cfd;
                    }
                  itype = build_index_type (itype);
                }
            }
          else if (decl_context == FIELD)
            {
              if (pedantic && !flag_isoc99 && !in_system_header)
                pedwarn ("ISO C90 does not support flexible array members");

              /* ISO C99 Flexible array members are effectively identical
                 to GCC's zero-length array extension.  */
              itype = build_range_type (sizetype, size_zero_node, NULL_TREE);
            }

          /* If pedantic, complain about arrays of incomplete types.  */

          if (pedantic && !COMPLETE_TYPE_P (type))
            pedwarn ("array type has incomplete element type");

#if 0
          /* We shouldn't have a function type here at all!
             Functions aren't allowed as array elements.  */
          if (pedantic && TREE_CODE (type) == FUNCTION_TYPE
              && (constp || volatilep))
            pedwarn ("ISO C forbids const or volatile function types");
#endif

          /* Build the array type itself, then merge any constancy or
             volatility into the target type.  We must do it in this order
             to ensure that the TYPE_MAIN_VARIANT field of the array type
             is set correctly.  */

          type = build_array_type (type, itype);
          if (type_quals)
            type = c_build_qualified_type (type, type_quals);

          if (size_varies)
            C_TYPE_VARIABLE_SIZE (type) = 1;

          /* The GCC extension for zero-length arrays differs from
             ISO flexible array members in that sizeof yields zero.  */
          if (size && integer_zerop (size))
            {
              layout_type (type);
              TYPE_SIZE (type) = bitsize_zero_node;
              TYPE_SIZE_UNIT (type) = size_zero_node;
            }
          if (decl_context != PARM
              && (array_ptr_quals != NULL_TREE || array_parm_static))
            {
              error ("static or type qualifiers in non-parameter array declarator");
              array_ptr_quals = NULL_TREE;
              array_parm_static = 0;
            }
        }
      else if (TREE_CODE (declarator) == CALL_EXPR)
        {
          tree arg_types;

          /* Declaring a function type.
             Make sure we have a valid type for the function to return.  */
          if (type == error_mark_node)
            continue;

          size_varies = 0;

          /* Warn about some types functions can't return.  */

          if (TREE_CODE (type) == FUNCTION_TYPE)
            {
              error ("`%s' declared as function returning a function", name);
              type = integer_type_node;
            }
          if (TREE_CODE (type) == ARRAY_TYPE)
            {
              error ("`%s' declared as function returning an array", name);
              type = integer_type_node;
            }

          /* Construct the function type and go to the next
             inner layer of declarator.  */

          arg_types = grokparms (TREE_OPERAND (declarator, 1),
                                 funcdef_flag
                                 /* Say it's a definition
                                    only for the CALL_EXPR
                                    closest to the identifier.  */
                                 && TREE_CODE (TREE_OPERAND (declarator, 0)) == IDENTIFIER_NODE);
          /* Type qualifiers before the return type of the function
             qualify the return type, not the function type.  */
          if (type_quals)
            {
              /* Type qualifiers on a function return type are normally
                 permitted by the standard but have no effect, so give a
                 warning at -Wextra.  Qualifiers on a void return type have
                 meaning as a GNU extension, and are banned on function
                 definitions in ISO C.  FIXME: strictly we shouldn't
                 pedwarn for qualified void return types except on function
                 definitions, but not doing so could lead to the undesirable
                 state of a "volatile void" function return type not being
                 warned about, and a use of the function being compiled
                 with GNU semantics, with no diagnostics under -pedantic.  */
              if (VOID_TYPE_P (type) && pedantic && !in_system_header)
                pedwarn ("ISO C forbids qualified void function return type");
              else if (extra_warnings
                       && !(VOID_TYPE_P (type)
                            && type_quals == TYPE_QUAL_VOLATILE))
                warning ("type qualifiers ignored on function return type");

              type = c_build_qualified_type (type, type_quals);
            }
          type_quals = TYPE_UNQUALIFIED;

          type = build_function_type (type, arg_types);
          declarator = TREE_OPERAND (declarator, 0);

          /* Set the TYPE_CONTEXTs for each tagged type which is local to
             the formal parameter list of this FUNCTION_TYPE to point to
             the FUNCTION_TYPE node itself.  */

          {
            tree link;

            for (link = last_function_parm_tags;
                 link;
                 link = TREE_CHAIN (link))
              TYPE_CONTEXT (TREE_VALUE (link)) = type;
          }
        }
      else if (TREE_CODE (declarator) == INDIRECT_REF)
        {
          /* Merge any constancy or volatility into the target type
             for the pointer.  */

          if (pedantic && TREE_CODE (type) == FUNCTION_TYPE
              && type_quals)
            pedwarn ("ISO C forbids qualified function types");
          if (type_quals)
            type = c_build_qualified_type (type, type_quals);
          type_quals = TYPE_UNQUALIFIED;
          size_varies = 0;

          type = build_pointer_type (type);

          /* Process a list of type modifier keywords
             (such as const or volatile) that were given inside the `*'.  */

          if (TREE_TYPE (declarator))
            {
              tree typemodlist;
              int erred = 0;

              constp = 0;
              volatilep = 0;
              restrictp = 0;
              for (typemodlist = TREE_TYPE (declarator); typemodlist;
                   typemodlist = TREE_CHAIN (typemodlist))
                {
                  tree qualifier = TREE_VALUE (typemodlist);

                  if (C_IS_RESERVED_WORD (qualifier))
                    {
                      if (C_RID_CODE (qualifier) == RID_CONST)
                        constp++;
                      else if (C_RID_CODE (qualifier) == RID_VOLATILE)
                        volatilep++;
                      else if (C_RID_CODE (qualifier) == RID_RESTRICT)
                        restrictp++;
                      else
                        erred++;
                    }
                  else
                    erred++;
                }

              if (erred)
                error ("invalid type modifier within pointer declarator");
              if (constp > 1 && ! flag_isoc99)
                pedwarn ("duplicate `const'");
              if (volatilep > 1 && ! flag_isoc99)
                pedwarn ("duplicate `volatile'");
              if (restrictp > 1 && ! flag_isoc99)
                pedwarn ("duplicate `restrict'");

              type_quals = ((constp ? TYPE_QUAL_CONST : 0)
                            | (restrictp ? TYPE_QUAL_RESTRICT : 0)
                            | (volatilep ? TYPE_QUAL_VOLATILE : 0));
            }

          declarator = TREE_OPERAND (declarator, 0);
        }
      else
        abort ();

    }

  /* Now TYPE has the actual type.  */

  /* Did array size calculations overflow?  */

  if (TREE_CODE (type) == ARRAY_TYPE
      && COMPLETE_TYPE_P (type)
      && TREE_OVERFLOW (TYPE_SIZE (type)))
    {
      error ("size of array `%s' is too large", name);
      /* If we proceed with the array type as it is, we'll eventually
         crash in tree_low_cst().  */
      type = error_mark_node;
    }

  /* If this is declaring a typedef name, return a TYPE_DECL.  */

  if (specbits & (1 << (int) RID_TYPEDEF))
    {
      tree decl;
      /* Note that the grammar rejects storage classes
         in typenames, fields or parameters */
      if (pedantic && TREE_CODE (type) == FUNCTION_TYPE
          && type_quals)
        pedwarn ("ISO C forbids qualified function types");
      if (type_quals)
        type = c_build_qualified_type (type, type_quals);
      decl = build_decl (TYPE_DECL, declarator, type);
      if ((specbits & (1 << (int) RID_SIGNED))
          || (typedef_decl && C_TYPEDEF_EXPLICITLY_SIGNED (typedef_decl)))
        C_TYPEDEF_EXPLICITLY_SIGNED (decl) = 1;
      decl_attributes (&decl, returned_attrs, 0);
      return decl;
    }

  /* Detect the case of an array type of unspecified size
     which came, as such, direct from a typedef name.
     We must copy the type, so that each identifier gets
     a distinct type, so that each identifier's size can be
     controlled separately by its own initializer.  */

  if (type != 0 && typedef_type != 0
      && TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type) == 0
      && TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (typedef_type))
    {
      type = build_array_type (TREE_TYPE (type), 0);
      if (size_varies)
        C_TYPE_VARIABLE_SIZE (type) = 1;
    }

  /* If this is a type name (such as, in a cast or sizeof),
     compute the type and return it now.  */

  if (decl_context == TYPENAME)
    {
      /* Note that the grammar rejects storage classes
         in typenames, fields or parameters */
      if (pedantic && TREE_CODE (type) == FUNCTION_TYPE
          && type_quals)
        pedwarn ("ISO C forbids const or volatile function types");
      if (type_quals)
        type = c_build_qualified_type (type, type_quals);
      decl_attributes (&type, returned_attrs, 0);
      return type;
    }

  /* Aside from typedefs and type names (handle above),
     `void' at top level (not within pointer)
     is allowed only in public variables.
     We don't complain about parms either, but that is because
     a better error message can be made later.  */

  if (VOID_TYPE_P (type) && decl_context != PARM
      && ! ((decl_context != FIELD && TREE_CODE (type) != FUNCTION_TYPE)
            && ((specbits & (1 << (int) RID_EXTERN))
                || (current_binding_level == global_binding_level
                    && !(specbits
                         & ((1 << (int) RID_STATIC) | (1 << (int) RID_REGISTER)))))))
    {
      error ("variable or field `%s' declared void", name);
      type = integer_type_node;
    }

  /* Now create the decl, which may be a VAR_DECL, a PARM_DECL
     or a FUNCTION_DECL, depending on DECL_CONTEXT and TYPE.  */

  {
    tree decl;

    if (decl_context == PARM)
      {
        tree type_as_written;
        tree promoted_type;

        /* A parameter declared as an array of T is really a pointer to T.
           One declared as a function is really a pointer to a function.  */

        if (TREE_CODE (type) == ARRAY_TYPE)
          {
            /* Transfer const-ness of array into that of type pointed to.  */
            type = TREE_TYPE (type);
            if (type_quals)
              type = c_build_qualified_type (type, type_quals);
            type = build_pointer_type (type);
            type_quals = TYPE_UNQUALIFIED;
            if (array_ptr_quals)
              {
                tree new_ptr_quals, new_ptr_attrs;
                int erred = 0;
                split_specs_attrs (array_ptr_quals, &new_ptr_quals, &new_ptr_attrs);
                /* We don't yet implement attributes in this context.  */
                if (new_ptr_attrs != NULL_TREE)
                  warning ("attributes in parameter array declarator ignored");

                constp = 0;
                volatilep = 0;
                restrictp = 0;
                for (; new_ptr_quals; new_ptr_quals = TREE_CHAIN (new_ptr_quals))
                  {
                    tree qualifier = TREE_VALUE (new_ptr_quals);

                    if (C_IS_RESERVED_WORD (qualifier))
                      {
                        if (C_RID_CODE (qualifier) == RID_CONST)
                          constp++;
                        else if (C_RID_CODE (qualifier) == RID_VOLATILE)
                          volatilep++;
                        else if (C_RID_CODE (qualifier) == RID_RESTRICT)
                          restrictp++;
                        else
                          erred++;
                      }
                    else
                      erred++;
                  }

                if (erred)
                  error ("invalid type modifier within array declarator");

                type_quals = ((constp ? TYPE_QUAL_CONST : 0)
                              | (restrictp ? TYPE_QUAL_RESTRICT : 0)
                              | (volatilep ? TYPE_QUAL_VOLATILE : 0));
              }
            size_varies = 0;
          }
        else if (TREE_CODE (type) == FUNCTION_TYPE)
          {
            if (pedantic && type_quals)
              pedwarn ("ISO C forbids qualified function types");
            if (type_quals)
              type = c_build_qualified_type (type, type_quals);
            type = build_pointer_type (type);
            type_quals = TYPE_UNQUALIFIED;
          }
        else if (type_quals)
          type = c_build_qualified_type (type, type_quals);
          
        type_as_written = type;

        decl = build_decl (PARM_DECL, declarator, type);
        if (size_varies)
          C_DECL_VARIABLE_SIZE (decl) = 1;

        /* Compute the type actually passed in the parmlist,
           for the case where there is no prototype.
           (For example, shorts and chars are passed as ints.)
           When there is a prototype, this is overridden later.  */

        if (type == error_mark_node)
          promoted_type = type;
        else
          promoted_type = c_type_promotes_to (type);

        DECL_ARG_TYPE (decl) = promoted_type;
        DECL_ARG_TYPE_AS_WRITTEN (decl) = type_as_written;
      }
    else if (decl_context == FIELD)
      {
        /* Structure field.  It may not be a function.  */

        if (TREE_CODE (type) == FUNCTION_TYPE)
          {
            error ("field `%s' declared as a function", name);
            type = build_pointer_type (type);
          }
        else if (TREE_CODE (type) != ERROR_MARK
                 && !COMPLETE_OR_UNBOUND_ARRAY_TYPE_P (type))
          {
            error ("field `%s' has incomplete type", name);
            type = error_mark_node;
          }
        /* Move type qualifiers down to element of an array.  */
        if (TREE_CODE (type) == ARRAY_TYPE && type_quals)
          {
            type = build_array_type (c_build_qualified_type (TREE_TYPE (type),
                                                             type_quals),
                                     TYPE_DOMAIN (type));
#if 0
            /* Leave the field const or volatile as well.  */
            type_quals = TYPE_UNQUALIFIED;
#endif
          }
        decl = build_decl (FIELD_DECL, declarator, type);
        DECL_NONADDRESSABLE_P (decl) = bitfield;

        if (size_varies)
          C_DECL_VARIABLE_SIZE (decl) = 1;
      }
    else if (TREE_CODE (type) == FUNCTION_TYPE)
      {
        /* Every function declaration is "external"
           except for those which are inside a function body
           in which `auto' is used.
           That is a case not specified by ANSI C,
           and we use it for forward declarations for nested functions.  */
        int extern_ref = (!(specbits & (1 << (int) RID_AUTO))
                          || current_binding_level == global_binding_level);

        if (specbits & (1 << (int) RID_AUTO)
            && (pedantic || current_binding_level == global_binding_level))
          pedwarn ("invalid storage class for function `%s'", name);
        if (specbits & (1 << (int) RID_REGISTER))
          error ("invalid storage class for function `%s'", name);
        if (specbits & (1 << (int) RID_THREAD))
          error ("invalid storage class for function `%s'", name);
        /* Function declaration not at top level.
           Storage classes other than `extern' are not allowed
           and `extern' makes no difference.  */
        if (current_binding_level != global_binding_level
            && (specbits & ((1 << (int) RID_STATIC) | (1 << (int) RID_INLINE)))
            && pedantic)
          pedwarn ("invalid storage class for function `%s'", name);

        decl = build_decl (FUNCTION_DECL, declarator, type);
        decl = build_decl_attribute_variant (decl, decl_attr);

        DECL_LANG_SPECIFIC (decl) = (struct lang_decl *)
          ggc_alloc_cleared (sizeof (struct lang_decl));

        if (pedantic && type_quals && ! DECL_IN_SYSTEM_HEADER (decl))
          pedwarn ("ISO C forbids qualified function types");

        /* GNU C interprets a `volatile void' return type to indicate
           that the function does not return.  */
        if ((type_quals & TYPE_QUAL_VOLATILE)
            && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
          warning ("`noreturn' function returns non-void value");

        if (extern_ref)
          DECL_EXTERNAL (decl) = 1;
        /* Record absence of global scope for `static' or `auto'.  */
        TREE_PUBLIC (decl)
          = !(specbits & ((1 << (int) RID_STATIC) | (1 << (int) RID_AUTO)));

        if (defaulted_int)
          C_FUNCTION_IMPLICIT_INT (decl) = 1;

        /* Record presence of `inline', if it is reasonable.  */
        if (MAIN_NAME_P (declarator))
          {
            if (inlinep)
              warning ("cannot inline function `main'");
          }
        else if (inlinep)
          {
            /* Assume that otherwise the function can be inlined.  */
            DECL_DECLARED_INLINE_P (decl) = 1;

            /* Do not mark bare declarations as DECL_INLINE.  Doing so
               in the presence of multiple declarations can result in
               the abstract origin pointing between the declarations,
               which will confuse dwarf2out.  */
            if (initialized)
              {
                DECL_INLINE (decl) = 1;
                if (specbits & (1 << (int) RID_EXTERN))
                  current_extern_inline = 1;
              }
          }
        /* If -finline-functions, assume it can be inlined.  This does
           two things: let the function be deferred until it is actually
           needed, and let dwarf2 know that the function is inlinable.  */
        else if (flag_inline_trees == 2 && initialized)
          {
            if (!DECL_INLINE (decl))
                DID_INLINE_FUNC (decl) = 1;
            DECL_INLINE (decl) = 1;
            DECL_DECLARED_INLINE_P (decl) = 0;
          }
      }
    else
      {
        /* It's a variable.  */
        /* An uninitialized decl with `extern' is a reference.  */
        int extern_ref = !initialized && (specbits & (1 << (int) RID_EXTERN));

        /* Move type qualifiers down to element of an array.  */
        if (TREE_CODE (type) == ARRAY_TYPE && type_quals)
          {
            int saved_align = TYPE_ALIGN(type);
            type = build_array_type (c_build_qualified_type (TREE_TYPE (type),
                                                             type_quals),
                                     TYPE_DOMAIN (type));
            TYPE_ALIGN (type) = saved_align;
#if 0 /* Leave the variable const or volatile as well.  */
            type_quals = TYPE_UNQUALIFIED;
#endif
          }
        else if (type_quals)
          type = c_build_qualified_type (type, type_quals);

        /* It is invalid to create an `extern' declaration for a
           variable if there is a global declaration that is
           `static'.  */
        if (extern_ref && current_binding_level != global_binding_level)
          {
            tree global_decl;

            global_decl = identifier_global_value (declarator);
            if (global_decl 
                && TREE_CODE (global_decl) == VAR_DECL
                && !TREE_PUBLIC (global_decl))
              error ("variable previously declared `static' redeclared "
                     "`extern'");
          }

        decl = build_decl (VAR_DECL, declarator, type);
        if (size_varies)
          C_DECL_VARIABLE_SIZE (decl) = 1;

        if (inlinep)
          pedwarn_with_decl (decl, "variable `%s' declared `inline'");

        DECL_EXTERNAL (decl) = extern_ref;

        /* At top level, the presence of a `static' or `register' storage
           class specifier, or the absence of all storage class specifiers
           makes this declaration a definition (perhaps tentative).  Also,
           the absence of both `static' and `register' makes it public.  */
        if (current_binding_level == global_binding_level)
          {
            TREE_PUBLIC (decl) = !(specbits & ((1 << (int) RID_STATIC)
                                               | (1 << (int) RID_REGISTER)));
            TREE_STATIC (decl) = !extern_ref;
          }
        /* Not at top level, only `static' makes a static definition.  */
        else
          {
            TREE_STATIC (decl) = (specbits & (1 << (int) RID_STATIC)) != 0;
            TREE_PUBLIC (decl) = extern_ref;
          }

        if (specbits & 1 << (int) RID_THREAD)
          {
            if (targetm.have_tls)
              DECL_THREAD_LOCAL (decl) = 1;
            else
              /* A mere warning is sure to result in improper semantics
                 at runtime.  Don't bother to allow this to compile.  */
              error ("thread-local storage not supported for this target");
          }
      }

    /* Record `register' declaration for warnings on &
       and in case doing stupid register allocation.  */

    if (specbits & (1 << (int) RID_REGISTER))
      DECL_REGISTER (decl) = 1;

    /* Record constancy and volatility.  */
    c_apply_type_quals_to_decl (type_quals, decl);

    /* If a type has volatile components, it should be stored in memory.
       Otherwise, the fact that those components are volatile
       will be ignored, and would even crash the compiler.  */
    if (C_TYPE_FIELDS_VOLATILE (TREE_TYPE (decl)))
      c_mark_addressable (decl);

    decl_attributes (&decl, returned_attrs, 0);

    return decl;
  }
}
\f
/* Decode the parameter-list info for a function type or function definition.
   The argument is the value returned by `get_parm_info' (or made in parse.y
   if there is an identifier list instead of a parameter decl list).
   These two functions are separate because when a function returns
   or receives functions then each is called multiple times but the order
   of calls is different.  The last call to `grokparms' is always the one
   that contains the formal parameter names of a function definition.

   Store in `last_function_parms' a chain of the decls of parms.
   Also store in `last_function_parm_tags' a chain of the struct, union,
   and enum tags declared among the parms.

   Return a list of arg types to use in the FUNCTION_TYPE for this function.

   FUNCDEF_FLAG is nonzero for a function definition, 0 for
   a mere declaration.  A nonempty identifier-list gets an error message
   when FUNCDEF_FLAG is zero.  */

static tree
grokparms (parms_info, funcdef_flag)
     tree parms_info;
     int funcdef_flag;
{
  tree first_parm = TREE_CHAIN (parms_info);

  last_function_parms = TREE_PURPOSE (parms_info);
  last_function_parm_tags = TREE_VALUE (parms_info);

  if (warn_strict_prototypes && first_parm == 0 && !funcdef_flag
      && !in_system_header)
    warning ("function declaration isn't a prototype");

  if (first_parm != 0
      && TREE_CODE (TREE_VALUE (first_parm)) == IDENTIFIER_NODE)
    {
      if (! funcdef_flag)
        pedwarn ("parameter names (without types) in function declaration");

      last_function_parms = first_parm;
      return 0;
    }
  else
    {
      tree parm;
      tree typelt;
      /* We no longer test FUNCDEF_FLAG.
         If the arg types are incomplete in a declaration,
         they must include undefined tags.
         These tags can never be defined in the scope of the declaration,
         so the types can never be completed,
         and no call can be compiled successfully.  */
#if 0
      /* In a fcn definition, arg types must be complete.  */
      if (funcdef_flag)
#endif
        for (parm = last_function_parms, typelt = first_parm;
             parm;
             parm = TREE_CHAIN (parm))
          /* Skip over any enumeration constants declared here.  */
          if (TREE_CODE (parm) == PARM_DECL)
            {
              /* Barf if the parameter itself has an incomplete type.  */
              tree type = TREE_VALUE (typelt);
              if (type == error_mark_node)
                continue;
              if (!COMPLETE_TYPE_P (type))
                {
                  if (funcdef_flag && DECL_NAME (parm) != 0)
                    error ("parameter `%s' has incomplete type",
                           IDENTIFIER_POINTER (DECL_NAME (parm)));
                  else
                    warning ("parameter has incomplete type");
                  if (funcdef_flag)
                    {
                      TREE_VALUE (typelt) = error_mark_node;
                      TREE_TYPE (parm) = error_mark_node;
                    }
                }
#if 0
              /* This has been replaced by parm_tags_warning, which
                 uses a more accurate criterion for what to warn
                 about.  */
              else
                {
                  /* Now warn if is a pointer to an incomplete type.  */
                  while (TREE_CODE (type) == POINTER_TYPE
                         || TREE_CODE (type) == REFERENCE_TYPE)
                    type = TREE_TYPE (type);
                  type = TYPE_MAIN_VARIANT (type);
                  if (!COMPLETE_TYPE_P (type))
                    {
                      if (DECL_NAME (parm) != 0)
                        warning ("parameter `%s' points to incomplete type",
                                 IDENTIFIER_POINTER (DECL_NAME (parm)));
                      else
                        warning ("parameter points to incomplete type");
                    }
                }
#endif
              typelt = TREE_CHAIN (typelt);
            }

      return first_parm;
    }
}

/* Return a tree_list node with info on a parameter list just parsed.
   The TREE_PURPOSE is a chain of decls of those parms.
   The TREE_VALUE is a list of structure, union and enum tags defined.
   The TREE_CHAIN is a list of argument types to go in the FUNCTION_TYPE.
   This tree_list node is later fed to `grokparms'.

   VOID_AT_END nonzero means append `void' to the end of the type-list.
   Zero means the parmlist ended with an ellipsis so don't append `void'.  */

tree
get_parm_info (void_at_end)
     int void_at_end;
{
  tree decl, t;
  tree types = 0;
  int erred = 0;
  tree tags = gettags ();
  tree parms = getdecls ();
  tree new_parms = 0;
  tree order = current_binding_level->parm_order;

  /* Just `void' (and no ellipsis) is special.  There are really no parms.
     But if the `void' is qualified (by `const' or `volatile') or has a
     storage class specifier (`register'), then the behavior is undefined;
     by not counting it as the special case of `void' we will cause an
     error later.  Typedefs for `void' are OK (see DR#157).  */
  if (void_at_end && parms != 0
      && TREE_CHAIN (parms) == 0
      && VOID_TYPE_P (TREE_TYPE (parms))
      && ! TREE_THIS_VOLATILE (parms)
      && ! TREE_READONLY (parms)
      && ! DECL_REGISTER (parms)
      && DECL_NAME (parms) == 0)
    {
      parms = NULL_TREE;
      storedecls (NULL_TREE);
      return tree_cons (NULL_TREE, NULL_TREE,
                        tree_cons (NULL_TREE, void_type_node, NULL_TREE));
    }

  /* Extract enumerator values and other non-parms declared with the parms.
     Likewise any forward parm decls that didn't have real parm decls.  */
  for (decl = parms; decl;)
    {
      tree next = TREE_CHAIN (decl);

      if (TREE_CODE (decl) != PARM_DECL)
        {
          TREE_CHAIN (decl) = new_parms;
          new_parms = decl;
        }
      else if (TREE_ASM_WRITTEN (decl))
        {
          error_with_decl (decl,
                           "parameter `%s' has just a forward declaration");
          TREE_CHAIN (decl) = new_parms;
          new_parms = decl;
        }
      decl = next;
    }

  /* Put the parm decls back in the order they were in in the parm list.  */
  for (t = order; t; t = TREE_CHAIN (t))
    {
      if (TREE_CHAIN (t))
        TREE_CHAIN (TREE_VALUE (t)) = TREE_VALUE (TREE_CHAIN (t));
      else
        TREE_CHAIN (TREE_VALUE (t)) = 0;
    }

  new_parms = chainon (order ? nreverse (TREE_VALUE (order)) : 0,
                       new_parms);

  /* Store the parmlist in the binding level since the old one
     is no longer a valid list.  (We have changed the chain pointers.)  */
  storedecls (new_parms);

  for (decl = new_parms; decl; decl = TREE_CHAIN (decl))
    /* There may also be declarations for enumerators if an enumeration
       type is declared among the parms.  Ignore them here.  */
    if (TREE_CODE (decl) == PARM_DECL)
      {
        /* Since there is a prototype,
           args are passed in their declared types.  */
        tree type = TREE_TYPE (decl);
        DECL_ARG_TYPE (decl) = type;
        if (PROMOTE_PROTOTYPES
            && INTEGRAL_TYPE_P (type)
            && TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node))
          DECL_ARG_TYPE (decl) = integer_type_node;

        types = tree_cons (NULL_TREE, TREE_TYPE (decl), types);
        if (VOID_TYPE_P (TREE_VALUE (types)) && ! erred
            && DECL_NAME (decl) == 0)
          {
            error ("`void' in parameter list must be the entire list");
            erred = 1;
          }
      }

  if (void_at_end)
    return tree_cons (new_parms, tags,
                      nreverse (tree_cons (NULL_TREE, void_type_node, types)));

  return tree_cons (new_parms, tags, nreverse (types));
}

/* At end of parameter list, warn about any struct, union or enum tags
   defined within.  Do so because these types cannot ever become complete.  */

void
parmlist_tags_warning ()
{
  tree elt;
  static int already;

  for (elt = current_binding_level->tags; elt; elt = TREE_CHAIN (elt))
    {
      enum tree_code code = TREE_CODE (TREE_VALUE (elt));
      /* An anonymous union parm type is meaningful as a GNU extension.
         So don't warn for that.  */
      if (code == UNION_TYPE && TREE_PURPOSE (elt) == 0 && !pedantic)
        continue;
      if (TREE_PURPOSE (elt) != 0)
        {
          if (code == RECORD_TYPE)
            warning ("`struct %s' declared inside parameter list",
                     IDENTIFIER_POINTER (TREE_PURPOSE (elt)));
          else if (code == UNION_TYPE)
            warning ("`union %s' declared inside parameter list",
                     IDENTIFIER_POINTER (TREE_PURPOSE (elt)));
          else
            warning ("`enum %s' declared inside parameter list",
                     IDENTIFIER_POINTER (TREE_PURPOSE (elt)));
        }
      else
        {
          /* For translation these need to be separate warnings */
          if (code == RECORD_TYPE)
            warning ("anonymous struct declared inside parameter list");
          else if (code == UNION_TYPE)
            warning ("anonymous union declared inside parameter list");
          else
            warning ("anonymous enum declared inside parameter list");
        }
      if (! already)
        {
          warning ("its scope is only this definition or declaration, which is probably not what you want");
          already = 1;
        }
    }
}
\f
/* Get the struct, enum or union (CODE says which) with tag NAME.
   Define the tag as a forward-reference if it is not defined.  */

tree
xref_tag (code, name)
     enum tree_code code;
     tree name;
{
  /* If a cross reference is requested, look up the type
     already defined for this tag and return it.  */

  tree ref = lookup_tag (code, name, 0);
  /* If this is the right type of tag, return what we found.
     (This reference will be shadowed by shadow_tag later if appropriate.)
     If this is the wrong type of tag, do not return it.  If it was the
     wrong type in the same binding level, we will have had an error
     message already; if in a different binding level and declaring
     a name, pending_xref_error will give an error message; but if in a
     different binding level and not declaring a name, this tag should
     shadow the previous declaration of a different type of tag, and
     this would not work properly if we return the reference found.
     (For example, with "struct foo" in an outer scope, "union foo;"
     must shadow that tag with a new one of union type.)  */
  if (ref && TREE_CODE (ref) == code)
    return ref;

  /* If no such tag is yet defined, create a forward-reference node
     and record it as the "definition".
     When a real declaration of this type is found,
     the forward-reference will be altered into a real type.  */

  ref = make_node (code);
  if (code == ENUMERAL_TYPE)
    {
      /* Give the type a default layout like unsigned int
         to avoid crashing if it does not get defined.  */
      TYPE_MODE (ref) = TYPE_MODE (unsigned_type_node);
      TYPE_ALIGN (ref) = TYPE_ALIGN (unsigned_type_node);
      TYPE_USER_ALIGN (ref) = 0;
      TREE_UNSIGNED (ref) = 1;
      TYPE_PRECISION (ref) = TYPE_PRECISION (unsigned_type_node);
      TYPE_MIN_VALUE (ref) = TYPE_MIN_VALUE (unsigned_type_node);
      TYPE_MAX_VALUE (ref) = TYPE_MAX_VALUE (unsigned_type_node);
    }

  pushtag (name, ref);

  return ref;
}
\f
/* Make sure that the tag NAME is defined *in the current binding level*
   at least as a forward reference.
   CODE says which kind of tag NAME ought to be.  */

tree
start_struct (code, name)
     enum tree_code code;
     tree name;
{
  /* If there is already a tag defined at this binding level
     (as a forward reference), just return it.  */

  tree ref = 0;

  if (name != 0)
    ref = lookup_tag (code, name, 1);
  if (ref && TREE_CODE (ref) == code)
    {
      if (TYPE_FIELDS (ref))
        {
          if (code == UNION_TYPE)
            error ("redefinition of `union %s'", IDENTIFIER_POINTER (name));
          else
            error ("redefinition of `struct %s'", IDENTIFIER_POINTER (name));
        }  
    }
  else
    {
      /* Otherwise create a forward-reference just so the tag is in scope.  */

      ref = make_node (code);
      pushtag (name, ref);
    }
  
  C_TYPE_BEING_DEFINED (ref) = 1;
  TYPE_PACKED (ref) = flag_pack_struct;
  return ref;
}

/* Process the specs, declarator (NULL if omitted) and width (NULL if omitted)
   of a structure component, returning a FIELD_DECL node.
   WIDTH is non-NULL for bit fields only, and is an INTEGER_CST node.

   This is done during the parsing of the struct declaration.
   The FIELD_DECL nodes are chained together and the lot of them
   are ultimately passed to `build_struct' to make the RECORD_TYPE node.  */

tree
grokfield (filename, line, declarator, declspecs, width)
     const char *filename ATTRIBUTE_UNUSED;
     int line ATTRIBUTE_UNUSED;
     tree declarator, declspecs, width;
{
  tree value;

  if (declarator == NULL_TREE && width == NULL_TREE)
    {
      /* This is an unnamed decl.

         If we have something of the form "union { list } ;" then this
         is the anonymous union extension.  Similarly for struct.

         If this is something of the form "struct foo;", then
           If MS extensions are enabled, this is handled as an
             anonymous struct.
           Otherwise this is a forward declaration of a structure tag.

         If this is something of the form "foo;" and foo is a TYPE_DECL, then
           If MS extensions are enabled and foo names a structure, then
             again this is an anonymous struct.
           Otherwise this is an error.

         Oh what a horrid tangled web we weave.  I wonder if MS consciously
         took this from Plan 9 or if it was an accident of implementation
         that took root before someone noticed the bug...  */

      tree type = TREE_VALUE (declspecs);

      if (flag_ms_extensions && TREE_CODE (type) == TYPE_DECL)
        type = TREE_TYPE (type);
      if (TREE_CODE (type) == RECORD_TYPE || TREE_CODE (type) == UNION_TYPE)
        {
          if (flag_ms_extensions)
            ; /* ok */
          else if (flag_iso)
            goto warn_unnamed_field;
          else if (TYPE_NAME (type) == NULL)
            ; /* ok */
          else
            goto warn_unnamed_field;
        }
      else
        {
        warn_unnamed_field:
          warning ("declaration does not declare anything");
          return NULL_TREE;
        }
    }

  value = grokdeclarator (declarator, declspecs, width ? BITFIELD : FIELD, 0);

  finish_decl (value, NULL_TREE, NULL_TREE);
  DECL_INITIAL (value) = width;

  if (flag_objc)
    objc_check_decl (value);
  return value;
}
\f
/* Fill in the fields of a RECORD_TYPE or UNION_TYPE node, T.
   FIELDLIST is a chain of FIELD_DECL nodes for the fields.
   ATTRIBUTES are attributes to be applied to the structure.  */

tree
finish_struct (t, fieldlist, attributes)
     tree t;
     tree fieldlist;
     tree attributes;
{
  tree x;
  int toplevel = global_binding_level == current_binding_level;
  int saw_named_field;

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

  TYPE_SIZE (t) = 0;

  decl_attributes (&t, attributes, (int) ATTR_FLAG_TYPE_IN_PLACE);

  /* Nameless union parm types are useful as GCC extension.  */
  if (! (TREE_CODE (t) == UNION_TYPE && TYPE_NAME (t) == 0) && !pedantic)
    /* Otherwise, warn about any struct or union def. in parmlist.  */
    if (in_parm_level_p ())
      {
        if (pedantic)
          pedwarn ("%s defined inside parms",
                   TREE_CODE (t) == UNION_TYPE ? _("union") : _("structure"));
        else
          warning ("%s defined inside parms",
                   TREE_CODE (t) == UNION_TYPE ? _("union") : _("structure"));
      }

  if (pedantic)
    {
      for (x = fieldlist; x; x = TREE_CHAIN (x))
        if (DECL_NAME (x) != 0)
          break;

      if (x == 0)
        pedwarn ("%s has no %s",
                 TREE_CODE (t) == UNION_TYPE ? _("union") : _("struct"),
                 fieldlist ? _("named members") : _("members"));
    }

  /* Install struct as DECL_CONTEXT of each field decl.
     Also process specified field sizes,m which is found in the DECL_INITIAL.
     Store 0 there, except for ": 0" fields (so we can find them
     and delete them, below).  */

  saw_named_field = 0;
  for (x = fieldlist; x; x = TREE_CHAIN (x))
    {
      DECL_CONTEXT (x) = t;
      DECL_PACKED (x) |= TYPE_PACKED (t);

      /* If any field is const, the structure type is pseudo-const.  */
      if (TREE_READONLY (x))
        C_TYPE_FIELDS_READONLY (t) = 1;
      else
        {
          /* A field that is pseudo-const makes the structure likewise.  */
          tree t1 = TREE_TYPE (x);
          while (TREE_CODE (t1) == ARRAY_TYPE)
            t1 = TREE_TYPE (t1);
          if ((TREE_CODE (t1) == RECORD_TYPE || TREE_CODE (t1) == UNION_TYPE)
              && C_TYPE_FIELDS_READONLY (t1))
            C_TYPE_FIELDS_READONLY (t) = 1;
        }

      /* Any field that is volatile means variables of this type must be
         treated in some ways as volatile.  */
      if (TREE_THIS_VOLATILE (x))
        C_TYPE_FIELDS_VOLATILE (t) = 1;

      /* Any field of nominal variable size implies structure is too.  */
      if (C_DECL_VARIABLE_SIZE (x))
        C_TYPE_VARIABLE_SIZE (t) = 1;

      /* Detect invalid nested redefinition.  */
      if (TREE_TYPE (x) == t)
        error ("nested redefinition of `%s'",
               IDENTIFIER_POINTER (TYPE_NAME (t)));

      /* Detect invalid bit-field size.  */
      if (DECL_INITIAL (x))
        STRIP_NOPS (DECL_INITIAL (x));
      if (DECL_INITIAL (x))
        {
          if (TREE_CODE (DECL_INITIAL (x)) == INTEGER_CST)
            constant_expression_warning (DECL_INITIAL (x));
          else
            {
              error_with_decl (x,
                               "bit-field `%s' width not an integer constant");
              DECL_INITIAL (x) = NULL;
            }
        }

      /* Detect invalid bit-field type.  */
      if (DECL_INITIAL (x)
          && TREE_CODE (TREE_TYPE (x)) != INTEGER_TYPE
          && TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE
          && TREE_CODE (TREE_TYPE (x)) != ENUMERAL_TYPE)
        {
          error_with_decl (x, "bit-field `%s' has invalid type");
          DECL_INITIAL (x) = NULL;
        }

      if (DECL_INITIAL (x) && pedantic
          && TYPE_MAIN_VARIANT (TREE_TYPE (x)) != integer_type_node
          && TYPE_MAIN_VARIANT (TREE_TYPE (x)) != unsigned_type_node
          && TYPE_MAIN_VARIANT (TREE_TYPE (x)) != c_bool_type_node
          /* Accept an enum that's equivalent to int or unsigned int.  */
          && !(TREE_CODE (TREE_TYPE (x)) == ENUMERAL_TYPE
               && (TYPE_PRECISION (TREE_TYPE (x))
                   == TYPE_PRECISION (integer_type_node))))
        pedwarn_with_decl (x, "bit-field `%s' type invalid in ISO C");

      /* Detect and ignore out of range field width and process valid
         field widths.  */
      if (DECL_INITIAL (x))
        {
          int max_width
            = (TYPE_MAIN_VARIANT (TREE_TYPE (x)) == c_bool_type_node
               ? CHAR_TYPE_SIZE : TYPE_PRECISION (TREE_TYPE (x)));

          if (tree_int_cst_sgn (DECL_INITIAL (x)) < 0)
            error_with_decl (x, "negative width in bit-field `%s'");
          else if (0 < compare_tree_int (DECL_INITIAL (x), max_width))
            pedwarn_with_decl (x, "width of `%s' exceeds its type");
          else if (integer_zerop (DECL_INITIAL (x)) && DECL_NAME (x) != 0)
            error_with_decl (x, "zero width for bit-field `%s'");
          else
            {
              /* The test above has assured us that TREE_INT_CST_HIGH is 0.  */
              unsigned HOST_WIDE_INT width
                = tree_low_cst (DECL_INITIAL (x), 1);

              if (TREE_CODE (TREE_TYPE (x)) == ENUMERAL_TYPE
                  && (width < min_precision (TYPE_MIN_VALUE (TREE_TYPE (x)),
                                             TREE_UNSIGNED (TREE_TYPE (x)))
                      || (width
                          < min_precision (TYPE_MAX_VALUE (TREE_TYPE (x)),
                                           TREE_UNSIGNED (TREE_TYPE (x))))))
                warning_with_decl (x,
                                   "`%s' is narrower than values of its type");

              DECL_SIZE (x) = bitsize_int (width);
              DECL_BIT_FIELD (x) = 1;
              SET_DECL_C_BIT_FIELD (x);
            }
        }

      DECL_INITIAL (x) = 0;

      /* Detect flexible array member in an invalid context.  */
      if (TREE_CODE (TREE_TYPE (x)) == ARRAY_TYPE
          && TYPE_SIZE (TREE_TYPE (x)) == NULL_TREE
          && TYPE_DOMAIN (TREE_TYPE (x)) != NULL_TREE
          && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (x))) == NULL_TREE)
        {
          if (TREE_CODE (t) == UNION_TYPE)
            error_with_decl (x, "flexible array member in union");
          else if (TREE_CHAIN (x) != NULL_TREE)
            error_with_decl (x, "flexible array member not at end of struct");
          else if (! saw_named_field)
            error_with_decl (x, "flexible array member in otherwise empty struct");
        }

      if (pedantic && TREE_CODE (t) == RECORD_TYPE
          && flexible_array_type_p (TREE_TYPE (x)))
        pedwarn_with_decl (x, "invalid use of structure with flexible array member");

      if (DECL_NAME (x))
        saw_named_field = 1;
    }

  /* Delete all duplicate fields from the fieldlist */
  for (x = fieldlist; x && TREE_CHAIN (x);)
    /* Anonymous fields aren't duplicates.  */
    if (DECL_NAME (TREE_CHAIN (x)) == 0)
      x = TREE_CHAIN (x);
    else
      {
        tree y = fieldlist;

        while (1)
          {
            if (DECL_NAME (y) == DECL_NAME (TREE_CHAIN (x)))
              break;
            if (y == x)
              break;
            y = TREE_CHAIN (y);
          }
        if (DECL_NAME (y) == DECL_NAME (TREE_CHAIN (x)))
          {
            error_with_decl (TREE_CHAIN (x), "duplicate member `%s'");
            TREE_CHAIN (x) = TREE_CHAIN (TREE_CHAIN (x));
          }
        else
          x = TREE_CHAIN (x);
      }

  /* Now we have the nearly final fieldlist.  Record it,
     then lay out the structure or union (including the fields).  */

  TYPE_FIELDS (t) = fieldlist;

  layout_type (t);

  /* Delete all zero-width bit-fields from the fieldlist */
  {
    tree *fieldlistp = &fieldlist;
    while (*fieldlistp)
      if (TREE_CODE (*fieldlistp) == FIELD_DECL && DECL_INITIAL (*fieldlistp))
        *fieldlistp = TREE_CHAIN (*fieldlistp);
      else
        fieldlistp = &TREE_CHAIN (*fieldlistp);
  }

  /* Now we have the truly final field list.
     Store it in this type and in the variants.  */

  TYPE_FIELDS (t) = fieldlist;

  for (x = TYPE_MAIN_VARIANT (t); x; x = TYPE_NEXT_VARIANT (x))
    {
      TYPE_FIELDS (x) = TYPE_FIELDS (t);
      TYPE_LANG_SPECIFIC (x) = TYPE_LANG_SPECIFIC (t);
      TYPE_ALIGN (x) = TYPE_ALIGN (t);
      TYPE_USER_ALIGN (x) = TYPE_USER_ALIGN (t);
    }

  /* If this was supposed to be a transparent union, but we can't
     make it one, warn and turn off the flag.  */
  if (TREE_CODE (t) == UNION_TYPE
      && TYPE_TRANSPARENT_UNION (t)
      && TYPE_MODE (t) != DECL_MODE (TYPE_FIELDS (t)))
    {
      TYPE_TRANSPARENT_UNION (t) = 0;
      warning ("union cannot be made transparent");
    }

  /* If this structure or union completes the type of any previous
     variable declaration, lay it out and output its rtl.  */

  if (current_binding_level->incomplete_list != NULL_TREE)
    {
      tree prev = NULL_TREE;

      for (x = current_binding_level->incomplete_list; x; x = TREE_CHAIN (x))
        {
          tree decl = TREE_VALUE (x);

          if (TYPE_MAIN_VARIANT (TREE_TYPE (decl)) == TYPE_MAIN_VARIANT (t)
              && TREE_CODE (decl) != TYPE_DECL)
            {
              layout_decl (decl, 0);
              /* This is a no-op in c-lang.c or something real in objc-act.c.  */
              if (flag_objc)
                objc_check_decl (decl);
              rest_of_decl_compilation (decl, NULL, toplevel, 0);
              if (! toplevel)
                expand_decl (decl);
              /* Unlink X from the incomplete list.  */
              if (prev)
                TREE_CHAIN (prev) = TREE_CHAIN (x);
              else
                current_binding_level->incomplete_list = TREE_CHAIN (x);
            }
          else if (!COMPLETE_TYPE_P (TREE_TYPE (decl))
                   && TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE)
            {
              tree element = TREE_TYPE (decl);
              while (TREE_CODE (element) == ARRAY_TYPE)
                element = TREE_TYPE (element);
              if (element == t)
                {
                  layout_array_type (TREE_TYPE (decl));
                  if (TREE_CODE (decl) != TYPE_DECL)
                    {
                      layout_decl (decl, 0);
                      if (flag_objc)
                        objc_check_decl (decl);
                      rest_of_decl_compilation (decl, NULL, toplevel, 0);
                      if (! toplevel)
                        expand_decl (decl);
                    }
                  /* Unlink X from the incomplete list.  */
                  if (prev)
                    TREE_CHAIN (prev) = TREE_CHAIN (x);
                  else
                    current_binding_level->incomplete_list = TREE_CHAIN (x);
                }
            }
        }
    }

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

  return t;
}

/* Lay out the type T, and its element type, and so on.  */

static void
layout_array_type (t)
     tree t;
{
  if (TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE)
    layout_array_type (TREE_TYPE (t));
  layout_type (t);
}
\f
/* Begin compiling the definition of an enumeration type.
   NAME is its name (or null if anonymous).
   Returns the type object, as yet incomplete.
   Also records info about it so that build_enumerator
   may be used to declare the individual values as they are read.  */

tree
start_enum (name)
     tree name;
{
  tree enumtype = 0;

  /* If this is the real definition for a previous forward reference,
     fill in the contents in the same object that used to be the
     forward reference.  */

  if (name != 0)
    enumtype = lookup_tag (ENUMERAL_TYPE, name, 1);

  if (enumtype == 0 || TREE_CODE (enumtype) != ENUMERAL_TYPE)
    {
      enumtype = make_node (ENUMERAL_TYPE);
      pushtag (name, enumtype);
    }

  C_TYPE_BEING_DEFINED (enumtype) = 1;

  if (TYPE_VALUES (enumtype) != 0)
    {
      /* This enum is a named one that has been declared already.  */
      error ("redeclaration of `enum %s'", IDENTIFIER_POINTER (name));

      /* Completely replace its old definition.
         The old enumerators remain defined, however.  */
      TYPE_VALUES (enumtype) = 0;
    }

  enum_next_value = integer_zero_node;
  enum_overflow = 0;

  if (flag_short_enums)
    TYPE_PACKED (enumtype) = 1;

  return enumtype;
}

/* After processing and defining all the values of an enumeration type,
   install their decls in the enumeration type and finish it off.
   ENUMTYPE is the type object, VALUES a list of decl-value pairs,
   and ATTRIBUTES are the specified attributes.
   Returns ENUMTYPE.  */

tree
finish_enum (enumtype, values, attributes)
     tree enumtype;
     tree values;
     tree attributes;
{
  tree pair, tem;
  tree minnode = 0, maxnode = 0, enum_value_type;
  int precision, unsign;
  int toplevel = (global_binding_level == current_binding_level);

  if (in_parm_level_p ())
    warning ("enum defined inside parms");

  decl_attributes (&enumtype, attributes, (int) ATTR_FLAG_TYPE_IN_PLACE);

  /* Calculate the maximum value of any enumerator in this type.  */

  if (values == error_mark_node)
    minnode = maxnode = integer_zero_node;
  else
    {
      minnode = maxnode = TREE_VALUE (values);
      for (pair = TREE_CHAIN (values); pair; pair = TREE_CHAIN (pair))
        {
          tree value = TREE_VALUE (pair);
          if (tree_int_cst_lt (maxnode, value))
            maxnode = value;
          if (tree_int_cst_lt (value, minnode))
            minnode = value;
        }
    }

  /* Construct the final type of this enumeration.  It is the same
     as one of the integral types - the narrowest one that fits, except
     that normally we only go as narrow as int - and signed iff any of
     the values are negative.  */
  unsign = (tree_int_cst_sgn (minnode) >= 0);
  precision = MAX (min_precision (minnode, unsign),
                   min_precision (maxnode, unsign));
  if (TYPE_PACKED (enumtype) || precision > TYPE_PRECISION (integer_type_node))
    {
      tree narrowest = c_common_type_for_size (precision, unsign);
      if (narrowest == 0)
        {
          warning ("enumeration values exceed range of largest integer");
          narrowest = long_long_integer_type_node;
        }

      precision = TYPE_PRECISION (narrowest);
    }
  else
    precision = TYPE_PRECISION (integer_type_node);

  if (precision == TYPE_PRECISION (integer_type_node))
    enum_value_type = c_common_type_for_size (precision, 0);
  else
    enum_value_type = enumtype;

  TYPE_MIN_VALUE (enumtype) = minnode;
  TYPE_MAX_VALUE (enumtype) = maxnode;
  TYPE_PRECISION (enumtype) = precision;
  TREE_UNSIGNED (enumtype) = unsign;
  TYPE_SIZE (enumtype) = 0;
  layout_type (enumtype);

  if (values != error_mark_node)
    {
      /* Change the type of the enumerators to be the enum type.  We
         need to do this irrespective of the size of the enum, for
         proper type checking.  Replace the DECL_INITIALs of the
         enumerators, and the value slots of the list, with copies
         that have the enum type; they cannot be modified in place
         because they may be shared (e.g.  integer_zero_node) Finally,
         change the purpose slots to point to the names of the decls.  */
      for (pair = values; pair; pair = TREE_CHAIN (pair))
        {
          tree enu = TREE_PURPOSE (pair);

          TREE_TYPE (enu) = enumtype;

          /* The ISO C Standard mandates enumerators to have type int,
             even though the underlying type of an enum type is
             unspecified.  Here we convert any enumerators that fit in
             an int to type int, to avoid promotions to unsigned types
             when comparing integers with enumerators that fit in the
             int range.  When -pedantic is given, build_enumerator()
             would have already taken care of those that don't fit.  */
          if (int_fits_type_p (DECL_INITIAL (enu), enum_value_type))
            DECL_INITIAL (enu) = convert (enum_value_type, DECL_INITIAL (enu));
          else
            DECL_INITIAL (enu) = convert (enumtype, DECL_INITIAL (enu));

          TREE_PURPOSE (pair) = DECL_NAME (enu);
          TREE_VALUE (pair) = DECL_INITIAL (enu);
        }

      TYPE_VALUES (enumtype) = values;
    }

  /* Fix up all variant types of this enum type.  */
  for (tem = TYPE_MAIN_VARIANT (enumtype); tem; tem = TYPE_NEXT_VARIANT (tem))
    {
      if (tem == enumtype)
        continue;
      TYPE_VALUES (tem) = TYPE_VALUES (enumtype);
      TYPE_MIN_VALUE (tem) = TYPE_MIN_VALUE (enumtype);
      TYPE_MAX_VALUE (tem) = TYPE_MAX_VALUE (enumtype);
      TYPE_SIZE (tem) = TYPE_SIZE (enumtype);
      TYPE_SIZE_UNIT (tem) = TYPE_SIZE_UNIT (enumtype);
      TYPE_MODE (tem) = TYPE_MODE (enumtype);
      TYPE_PRECISION (tem) = TYPE_PRECISION (enumtype);
      TYPE_ALIGN (tem) = TYPE_ALIGN (enumtype);
      TYPE_USER_ALIGN (tem) = TYPE_USER_ALIGN (enumtype);
      TREE_UNSIGNED (tem) = TREE_UNSIGNED (enumtype);
    }

  /* Finish debugging output for this type.  */
  rest_of_type_compilation (enumtype, toplevel);

  return enumtype;
}

/* Build and install a CONST_DECL for one value of the
   current enumeration type (one that was begun with start_enum).
   Return a tree-list containing the CONST_DECL and its value.
   Assignment of sequential values by default is handled here.  */

tree
build_enumerator (name, value)
     tree name, value;
{
  tree decl, type;

  /* Validate and default VALUE.  */

  /* Remove no-op casts from the value.  */
  if (value)
    STRIP_TYPE_NOPS (value);

  if (value != 0)
    {
      if (TREE_CODE (value) == INTEGER_CST)
        {
          value = default_conversion (value);
          constant_expression_warning (value);
        }
      else
        {
          error ("enumerator value for `%s' not integer constant",
                 IDENTIFIER_POINTER (name));
          value = 0;
        }
    }

  /* Default based on previous value.  */
  /* It should no longer be possible to have NON_LVALUE_EXPR
     in the default.  */
  if (value == 0)
    {
      value = enum_next_value;
      if (enum_overflow)
        error ("overflow in enumeration values");
    }

  if (pedantic && ! int_fits_type_p (value, integer_type_node))
    {
      pedwarn ("ISO C restricts enumerator values to range of `int'");
      value = convert (integer_type_node, value);
    }

  /* Set basis for default for next value.  */
  enum_next_value = build_binary_op (PLUS_EXPR, value, integer_one_node, 0);
  enum_overflow = tree_int_cst_lt (enum_next_value, value);

  /* Now create a declaration for the enum value name.  */

  type = TREE_TYPE (value);
  type = c_common_type_for_size (MAX (TYPE_PRECISION (type),
                                      TYPE_PRECISION (integer_type_node)),
                                 (TYPE_PRECISION (type)
                                  >= TYPE_PRECISION (integer_type_node)
                                  && TREE_UNSIGNED (type)));

  decl = build_decl (CONST_DECL, name, type);
  DECL_INITIAL (decl) = convert (type, value);
  pushdecl (decl);

  return tree_cons (decl, value, NULL_TREE);
}

\f
/* Create the FUNCTION_DECL for a function definition.
   DECLSPECS, DECLARATOR and ATTRIBUTES are the parts of
   the declaration; they describe the function's name and the type it returns,
   but twisted together in a fashion that parallels the syntax of C.

   This function creates a binding context for the function body
   as well as setting up the FUNCTION_DECL in current_function_decl.

   Returns 1 on success.  If the DECLARATOR is not suitable for a function
   (it defines a datum instead), we return 0, which tells
   yyparse to report a parse error.  */

int
start_function (declspecs, declarator, attributes)
     tree declarator, declspecs, attributes;
{
  tree decl1, old_decl;
  tree restype;
  int old_immediate_size_expand = immediate_size_expand;

  current_function_returns_value = 0;  /* Assume, until we see it does.  */
  current_function_returns_null = 0;
  current_function_returns_abnormally = 0;
  warn_about_return_type = 0;
  current_extern_inline = 0;
  named_labels = 0;
  shadowed_labels = 0;

  /* Don't expand any sizes in the return type of the function.  */
  immediate_size_expand = 0;

  decl1 = grokdeclarator (declarator, declspecs, FUNCDEF, 1);

  /* If the declarator is not suitable for a function definition,
     cause a syntax error.  */
  if (decl1 == 0)
    {
      immediate_size_expand = old_immediate_size_expand;
      return 0;
    }

  decl_attributes (&decl1, attributes, 0);

  /* If #pragma weak was used, mark the decl weak now.  */
  if (current_binding_level == global_binding_level)
    maybe_apply_pragma_weak (decl1);

  if (DECL_DECLARED_INLINE_P (decl1)
      && DECL_UNINLINABLE (decl1)
      && lookup_attribute ("noinline", DECL_ATTRIBUTES (decl1)))
    warning_with_decl (decl1,
                       "inline function `%s' given attribute noinline");

  announce_function (decl1);

  if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl1))))
    {
      error ("return type is an incomplete type");
      /* Make it return void instead.  */
      TREE_TYPE (decl1)
        = build_function_type (void_type_node,
                               TYPE_ARG_TYPES (TREE_TYPE (decl1)));
    }

  if (warn_about_return_type)
    pedwarn_c99 ("return type defaults to `int'");

  /* Save the parm names or decls from this function's declarator
     where store_parm_decls will find them.  */
  current_function_parms = last_function_parms;
  current_function_parm_tags = last_function_parm_tags;

  /* Make the init_value nonzero so pushdecl knows this is not tentative.
     error_mark_node is replaced below (in poplevel) with the BLOCK.  */
  DECL_INITIAL (decl1) = error_mark_node;

  /* If this definition isn't a prototype and we had a prototype declaration
     before, copy the arg type info from that prototype.
     But not if what we had before was a builtin function.  */
  old_decl = lookup_name_current_level (DECL_NAME (decl1));
  if (old_decl != 0 && TREE_CODE (TREE_TYPE (old_decl)) == FUNCTION_TYPE
      && !DECL_BUILT_IN (old_decl)
      && (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (decl1)))
          == TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (old_decl))))
      && TYPE_ARG_TYPES (TREE_TYPE (decl1)) == 0)
    {
      TREE_TYPE (decl1) = TREE_TYPE (old_decl);
      current_function_prototype_file = DECL_SOURCE_FILE (old_decl);
      current_function_prototype_line = DECL_SOURCE_LINE (old_decl);
    }

  /* Optionally warn of old-fashioned def with no previous prototype.  */
  if (warn_strict_prototypes
      && TYPE_ARG_TYPES (TREE_TYPE (decl1)) == 0
      && C_DECL_ISNT_PROTOTYPE (old_decl))
    warning ("function declaration isn't a prototype");
  /* Optionally warn of any global def with no previous prototype.  */
  else if (warn_missing_prototypes
           && TREE_PUBLIC (decl1)
           && ! MAIN_NAME_P (DECL_NAME (decl1))
           && C_DECL_ISNT_PROTOTYPE (old_decl))
    warning_with_decl (decl1, "no previous prototype for `%s'");
  /* Optionally warn of any def with no previous prototype
     if the function has already been used.  */
  else if (warn_missing_prototypes
           && old_decl != 0 && TREE_USED (old_decl)
           && TYPE_ARG_TYPES (TREE_TYPE (old_decl)) == 0)
    warning_with_decl (decl1,
                       "`%s' was used with no prototype before its definition");
  /* Optionally warn of any global def with no previous declaration.  */
  else if (warn_missing_declarations
           && TREE_PUBLIC (decl1)
           && old_decl == 0
           && ! MAIN_NAME_P (DECL_NAME (decl1)))
    warning_with_decl (decl1, "no previous declaration for `%s'");
  /* Optionally warn of any def with no previous declaration
     if the function has already been used.  */
  else if (warn_missing_declarations
           && old_decl != 0 && TREE_USED (old_decl)
           && C_DECL_IMPLICIT (old_decl))
    warning_with_decl (decl1,
                       "`%s' was used with no declaration before its definition");

  /* This is a definition, not a reference.
     So normally clear DECL_EXTERNAL.
     However, `extern inline' acts like a declaration
     except for defining how to inline.  So set DECL_EXTERNAL in that case.  */
  DECL_EXTERNAL (decl1) = current_extern_inline;

  /* This function exists in static storage.
     (This does not mean `static' in the C sense!)  */
  TREE_STATIC (decl1) = 1;

  /* A nested function is not global.  */
  if (current_function_decl != 0)
    TREE_PUBLIC (decl1) = 0;

  /* Warn for unlikely, improbable, or stupid declarations of `main'.  */
  if (warn_main > 0 && MAIN_NAME_P (DECL_NAME (decl1)))
    {
      tree args;
      int argct = 0;

      if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (decl1)))
          != integer_type_node)
        pedwarn_with_decl (decl1, "return type of `%s' is not `int'");

      for (args = TYPE_ARG_TYPES (TREE_TYPE (decl1)); args;
           args = TREE_CHAIN (args))
        {
          tree type = args ? TREE_VALUE (args) : 0;

          if (type == void_type_node)
            break;

          ++argct;
          switch (argct)
            {
            case 1:
              if (TYPE_MAIN_VARIANT (type) != integer_type_node)
                pedwarn_with_decl (decl1,
                                   "first argument of `%s' should be `int'");
              break;

            case 2:
              if (TREE_CODE (type) != POINTER_TYPE
                  || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
                  || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
                      != char_type_node))
                pedwarn_with_decl (decl1,
                                   "second argument of `%s' should be `char **'");
              break;

            case 3:
              if (TREE_CODE (type) != POINTER_TYPE
                  || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE
                  || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type)))
                      != char_type_node))
                pedwarn_with_decl (decl1,
                                   "third argument of `%s' should probably be `char **'");
              break;
            }
        }

      /* It is intentional that this message does not mention the third
         argument because it's only mentioned in an appendix of the
         standard.  */
      if (argct > 0 && (argct < 2 || argct > 3))
        pedwarn_with_decl (decl1, "`%s' takes only zero or two arguments");

      if (! TREE_PUBLIC (decl1))
        pedwarn_with_decl (decl1, "`%s' is normally a non-static function");
    }

  /* Record the decl so that the function name is defined.
     If we already have a decl for this name, and it is a FUNCTION_DECL,
     use the old decl.  */

  current_function_decl = pushdecl (decl1);

  pushlevel (0);
  declare_parm_level (1);

  make_decl_rtl (current_function_decl, NULL);

  restype = TREE_TYPE (TREE_TYPE (current_function_decl));
  /* Promote the value to int before returning it.  */
  if (c_promoting_integer_type_p (restype))
    {
      /* It retains unsignedness if not really getting wider.  */
      if (TREE_UNSIGNED (restype)
          && (TYPE_PRECISION (restype)
                  == TYPE_PRECISION (integer_type_node)))
        restype = unsigned_type_node;
      else
        restype = integer_type_node;
    }
  DECL_RESULT (current_function_decl)
    = build_decl (RESULT_DECL, NULL_TREE, restype);

  /* If this fcn was already referenced via a block-scope `extern' decl
     (or an implicit decl), propagate certain information about the usage.  */
  if (TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (current_function_decl)))
    TREE_ADDRESSABLE (current_function_decl) = 1;

  immediate_size_expand = old_immediate_size_expand;

  start_fname_decls ();
  
  return 1;
}
\f
/* Store the parameter declarations into the current function declaration.
   This is called after parsing the parameter declarations, before
   digesting the body of the function.

   For an old-style definition, modify the function's type
   to specify at least the number of arguments.  */

void
store_parm_decls ()
{
  tree fndecl = current_function_decl;
  tree parm;

  /* This is either a chain of PARM_DECLs (if a prototype was used)
     or a list of IDENTIFIER_NODEs (for an old-fashioned C definition).  */
  tree specparms = current_function_parms;

  /* This is a list of types declared among parms in a prototype.  */
  tree parmtags = current_function_parm_tags;

  /* This is a chain of PARM_DECLs from old-style parm declarations.  */
  tree parmdecls = getdecls ();

  /* This is a chain of any other decls that came in among the parm
     declarations.  If a parm is declared with  enum {foo, bar} x;
     then CONST_DECLs for foo and bar are put here.  */
  tree nonparms = 0;

  /* The function containing FNDECL, if any.  */
  tree context = decl_function_context (fndecl);

  /* Nonzero if this definition is written with a prototype.  */
  int prototype = 0;

  int saved_warn_shadow = warn_shadow;

  /* Don't re-emit shadow warnings.  */
  warn_shadow = 0;

  if (specparms != 0 && TREE_CODE (specparms) != TREE_LIST)
    {
      /* This case is when the function was defined with an ANSI prototype.
         The parms already have decls, so we need not do anything here
         except record them as in effect
         and complain if any redundant old-style parm decls were written.  */

      tree next;
      tree others = 0;

      prototype = 1;

      if (parmdecls != 0)
        {
          tree decl, link;

          error_with_decl (fndecl,
                           "parm types given both in parmlist and separately");
          /* Get rid of the erroneous decls; don't keep them on
             the list of parms, since they might not be PARM_DECLs.  */
          for (decl = current_binding_level->names;
               decl; decl = TREE_CHAIN (decl))
            if (DECL_NAME (decl))
              IDENTIFIER_SYMBOL_VALUE (DECL_NAME (decl)) = 0;
          for (link = current_binding_level->shadowed;
               link; link = TREE_CHAIN (link))
            IDENTIFIER_SYMBOL_VALUE (TREE_PURPOSE (link)) = TREE_VALUE (link);
          current_binding_level->names = 0;
          current_binding_level->shadowed = 0;
        }

      specparms = nreverse (specparms);
      for (parm = specparms; parm; parm = next)
        {
          next = TREE_CHAIN (parm);
          if (TREE_CODE (parm) == PARM_DECL)
            {
              if (DECL_NAME (parm) == 0)
                error_with_decl (parm, "parameter name omitted");
              else if (TREE_CODE (TREE_TYPE (parm)) != ERROR_MARK
                       && VOID_TYPE_P (TREE_TYPE (parm)))
                {
                  error_with_decl (parm, "parameter `%s' declared void");
                  /* Change the type to error_mark_node so this parameter
                     will be ignored by assign_parms.  */
                  TREE_TYPE (parm) = error_mark_node;
                }
              pushdecl (parm);
            }
          else
            {
              /* If we find an enum constant or a type tag,
                 put it aside for the moment.  */
              TREE_CHAIN (parm) = 0;
              others = chainon (others, parm);
            }
        }

      /* Get the decls in their original chain order
         and record in the function.  */
      DECL_ARGUMENTS (fndecl) = getdecls ();

#if 0
      /* If this function takes a variable number of arguments,
         add a phony parameter to the end of the parm list,
         to represent the position of the first unnamed argument.  */
      if (TREE_VALUE (tree_last (TYPE_ARG_TYPES (TREE_TYPE (fndecl))))
          != void_type_node)
        {
          tree dummy = build_decl (PARM_DECL, NULL_TREE, void_type_node);
          /* Let's hope the address of the unnamed parm
             won't depend on its type.  */
          TREE_TYPE (dummy) = integer_type_node;
          DECL_ARG_TYPE (dummy) = integer_type_node;
          DECL_ARGUMENTS (fndecl) = chainon (DECL_ARGUMENTS (fndecl), dummy);
        }
#endif

      /* Now pushdecl the enum constants.  */
      for (parm = others; parm; parm = next)
        {
          next = TREE_CHAIN (parm);
          if (DECL_NAME (parm) == 0)
            ;
          else if (TYPE_MAIN_VARIANT (TREE_TYPE (parm)) == void_type_node)
            ;
          else if (TREE_CODE (parm) != PARM_DECL)
            pushdecl (parm);
        }

      storetags (chainon (parmtags, gettags ()));
    }
  else
    {
      /* SPECPARMS is an identifier list--a chain of TREE_LIST nodes
         each with a parm name as the TREE_VALUE.

         PARMDECLS is a chain of declarations for parameters.
         Warning! It can also contain CONST_DECLs which are not parameters
         but are names of enumerators of any enum types
         declared among the parameters.

         First match each formal parameter name with its declaration.
         Associate decls with the names and store the decls
         into the TREE_PURPOSE slots.  */

      /* We use DECL_WEAK as a flag to show which parameters have been
         seen already since it is not used on PARM_DECL or CONST_DECL.  */
      for (parm = parmdecls; parm; parm = TREE_CHAIN (parm))
        DECL_WEAK (parm) = 0;

      for (parm = specparms; parm; parm = TREE_CHAIN (parm))
        {
          tree tail, found = NULL;

          if (TREE_VALUE (parm) == 0)
            {
              error_with_decl (fndecl,
                               "parameter name missing from parameter list");
              TREE_PURPOSE (parm) = 0;
              continue;
            }

          /* See if any of the parmdecls specifies this parm by name.
             Ignore any enumerator decls.  */
          for (tail = parmdecls; tail; tail = TREE_CHAIN (tail))
            if (DECL_NAME (tail) == TREE_VALUE (parm)
                && TREE_CODE (tail) == PARM_DECL)
              {
                found = tail;
                break;
              }

          /* If declaration already marked, we have a duplicate name.
             Complain, and don't use this decl twice.  */
          if (found && DECL_WEAK (found))
            {
              error_with_decl (found, "multiple parameters named `%s'");
              found = 0;
            }

          /* If the declaration says "void", complain and ignore it.  */
          if (found && VOID_TYPE_P (TREE_TYPE (found)))
            {
              error_with_decl (found, "parameter `%s' declared void");
              TREE_TYPE (found) = integer_type_node;
              DECL_ARG_TYPE (found) = integer_type_node;
              layout_decl (found, 0);
            }

          /* If no declaration found, default to int.  */
          if (!found)
            {
              found = build_decl (PARM_DECL, TREE_VALUE (parm),
                                  integer_type_node);
              DECL_ARG_TYPE (found) = TREE_TYPE (found);
              DECL_SOURCE_LINE (found) = DECL_SOURCE_LINE (fndecl);
              DECL_SOURCE_FILE (found) = DECL_SOURCE_FILE (fndecl);
              if (flag_isoc99)
                pedwarn_with_decl (found, "type of `%s' defaults to `int'");
              else if (extra_warnings)
                warning_with_decl (found, "type of `%s' defaults to `int'");
              pushdecl (found);
            }

          TREE_PURPOSE (parm) = found;

          /* Mark this decl as "already found".  */
          DECL_WEAK (found) = 1;
        }

      /* Put anything which is on the parmdecls chain and which is
         not a PARM_DECL onto the list NONPARMS.  (The types of
         non-parm things which might appear on the list include
         enumerators and NULL-named TYPE_DECL nodes.) Complain about
         any actual PARM_DECLs not matched with any names.  */

      nonparms = 0;
      for (parm = parmdecls; parm;)
        {
          tree next = TREE_CHAIN (parm);
          TREE_CHAIN (parm) = 0;

          if (TREE_CODE (parm) != PARM_DECL)
            nonparms = chainon (nonparms, parm);
          else
            {
              /* Complain about args with incomplete types.  */
              if (!COMPLETE_TYPE_P (TREE_TYPE (parm)))
                {
                  error_with_decl (parm, "parameter `%s' has incomplete type");
                  TREE_TYPE (parm) = error_mark_node;
                }

              if (! DECL_WEAK (parm))
                {
                  error_with_decl (parm,
                                   "declaration for parameter `%s' but no such parameter");
                  /* Pretend the parameter was not missing.
                     This gets us to a standard state and minimizes
                     further error messages.  */
                  specparms
                    = chainon (specparms,
                               tree_cons (parm, NULL_TREE, NULL_TREE));
                }
            }

          parm = next;
        }

      /* Chain the declarations together in the order of the list of
         names.  Store that chain in the function decl, replacing the
         list of names.  */
      parm = specparms;
      DECL_ARGUMENTS (fndecl) = 0;
      {
        tree last;
        for (last = 0; parm; parm = TREE_CHAIN (parm))
          if (TREE_PURPOSE (parm))
            {
              if (last == 0)
                DECL_ARGUMENTS (fndecl) = TREE_PURPOSE (parm);
              else
                TREE_CHAIN (last) = TREE_PURPOSE (parm);
              last = TREE_PURPOSE (parm);
              TREE_CHAIN (last) = 0;
            }
      }

      /* If there was a previous prototype,
         set the DECL_ARG_TYPE of each argument according to
         the type previously specified, and report any mismatches.  */

      if (TYPE_ARG_TYPES (TREE_TYPE (fndecl)))
        {
          tree type;
          for (parm = DECL_ARGUMENTS (fndecl),
               type = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
               parm || (type && (TYPE_MAIN_VARIANT (TREE_VALUE (type))
                                 != void_type_node));
               parm = TREE_CHAIN (parm), type = TREE_CHAIN (type))
            {
              if (parm == 0 || type == 0
                  || TYPE_MAIN_VARIANT (TREE_VALUE (type)) == void_type_node)
                {
                  error ("number of arguments doesn't match prototype");
                  error_with_file_and_line (current_function_prototype_file,
                                            current_function_prototype_line,
                                            "prototype declaration");
                  break;
                }
              /* Type for passing arg must be consistent with that
                 declared for the arg.  ISO C says we take the unqualified
                 type for parameters declared with qualified type.  */
              if (! comptypes (TYPE_MAIN_VARIANT (DECL_ARG_TYPE (parm)),
                               TYPE_MAIN_VARIANT (TREE_VALUE (type))))
                {
                  if (TYPE_MAIN_VARIANT (TREE_TYPE (parm))
                      == TYPE_MAIN_VARIANT (TREE_VALUE (type)))
                    {
                      /* Adjust argument to match prototype.  E.g. a previous
                         `int foo(float);' prototype causes
                         `int foo(x) float x; {...}' to be treated like
                         `int foo(float x) {...}'.  This is particularly
                         useful for argument types like uid_t.  */
                      DECL_ARG_TYPE (parm) = TREE_TYPE (parm);

                      if (PROMOTE_PROTOTYPES
                          && INTEGRAL_TYPE_P (TREE_TYPE (parm))
                          && TYPE_PRECISION (TREE_TYPE (parm))
                          < TYPE_PRECISION (integer_type_node))
                        DECL_ARG_TYPE (parm) = integer_type_node;

                      if (pedantic)
                        {
                          pedwarn ("promoted argument `%s' doesn't match prototype",
                                   IDENTIFIER_POINTER (DECL_NAME (parm)));
                          warning_with_file_and_line
                            (current_function_prototype_file,
                             current_function_prototype_line,
                             "prototype declaration");
                        }
                    }
                  else
                    {
                      error ("argument `%s' doesn't match prototype",
                             IDENTIFIER_POINTER (DECL_NAME (parm)));
                      error_with_file_and_line (current_function_prototype_file,
                                                current_function_prototype_line,
                                                "prototype declaration");
                    }
                }
            }
          TYPE_ACTUAL_ARG_TYPES (TREE_TYPE (fndecl)) = 0;
        }

      /* Otherwise, create a prototype that would match.  */

      else
        {
          tree actual = 0, last = 0, type;

          for (parm = DECL_ARGUMENTS (fndecl); parm; parm = TREE_CHAIN (parm))
            {
              type = tree_cons (NULL_TREE, DECL_ARG_TYPE (parm), NULL_TREE);
              if (last)
                TREE_CHAIN (last) = type;
              else
                actual = type;
              last = type;
            }
          type = tree_cons (NULL_TREE, void_type_node, NULL_TREE);
          if (last)
            TREE_CHAIN (last) = type;
          else
            actual = type;

          /* We are going to assign a new value for the TYPE_ACTUAL_ARG_TYPES
             of the type of this function, but we need to avoid having this
             affect the types of other similarly-typed functions, so we must
             first force the generation of an identical (but separate) type
             node for the relevant function type.  The new node we create
             will be a variant of the main variant of the original function
             type.  */

          TREE_TYPE (fndecl) = build_type_copy (TREE_TYPE (fndecl));

          TYPE_ACTUAL_ARG_TYPES (TREE_TYPE (fndecl)) = actual;
        }

      /* Now store the final chain of decls for the arguments
         as the decl-chain of the current lexical scope.
         Put the enumerators in as well, at the front so that
         DECL_ARGUMENTS is not modified.  */

      storedecls (chainon (nonparms, DECL_ARGUMENTS (fndecl)));
    }

  /* Make sure the binding level for the top of the function body
     gets a BLOCK if there are any in the function.
     Otherwise, the dbx output is wrong.  */

  keep_next_if_subblocks = 1;

  /* ??? This might be an improvement,
     but needs to be thought about some more.  */
#if 0
  keep_next_level_flag = 1;
#endif

  /* Write a record describing this function definition to the prototypes
     file (if requested).  */

  gen_aux_info_record (fndecl, 1, 0, prototype);

  /* Initialize the RTL code for the function.  */
  init_function_start (fndecl, input_filename, input_line);

  /* Begin the statement tree for this function.  */
  begin_stmt_tree (&DECL_SAVED_TREE (current_function_decl));

  /* If this is a nested function, save away the sizes of any
     variable-size types so that we can expand them when generating
     RTL.  */
  if (context)
    {
      tree t;

      DECL_LANG_SPECIFIC (fndecl)->pending_sizes 
        = nreverse (get_pending_sizes ());
      for (t = DECL_LANG_SPECIFIC (fndecl)->pending_sizes;
           t;
           t = TREE_CHAIN (t))
        SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = context;
    }

  /* This function is being processed in whole-function mode.  */
  cfun->x_whole_function_mode_p = 1;

  /* Even though we're inside a function body, we still don't want to
     call expand_expr to calculate the size of a variable-sized array.
     We haven't necessarily assigned RTL to all variables yet, so it's
     not safe to try to expand expressions involving them.  */
  immediate_size_expand = 0;
  cfun->x_dont_save_pending_sizes_p = 1;

  warn_shadow = saved_warn_shadow;
}
\f
/* Finish up a function declaration and compile that function
   all the way to assembler language output.  The free the storage
   for the function definition.

   This is called after parsing the body of the function definition.

   NESTED is nonzero if the function being finished is nested in another.
   CAN_DEFER_P is nonzero if the function may be deferred.  */

void
finish_function (nested, can_defer_p)
     int nested;
     int can_defer_p;
{
  tree fndecl = current_function_decl;

  /* When a function declaration is totally empty, e.g.
        void foo(void) { }
     (the argument list is irrelevant) the compstmt rule will not
     bother calling pushlevel/poplevel, which means we get here with
     the binding_level stack out of sync.  Detect this situation by
     noticing that the current_binding_level is still as
     store_parm_decls left it, and do a dummy push/pop to get back to
     consistency.  Note that the call to pushlevel does not actually
     push another binding level - see there for details.  */
  if (current_binding_level->parm_flag && keep_next_if_subblocks)
    {
      pushlevel (0);
      poplevel (1, 0, 1);
    }

#if 0
  /* This caused &foo to be of type ptr-to-const-function which then
     got a warning when stored in a ptr-to-function variable.  */
  TREE_READONLY (fndecl) = 1;
#endif

  BLOCK_SUPERCONTEXT (DECL_INITIAL (fndecl)) = fndecl;

  /* Must mark the RESULT_DECL as being in this function.  */

  DECL_CONTEXT (DECL_RESULT (fndecl)) = fndecl;

  if (MAIN_NAME_P (DECL_NAME (fndecl)) && flag_hosted)
    {
      if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (fndecl)))
          != integer_type_node)
        {
          /* If warn_main is 1 (-Wmain) or 2 (-Wall), we have already warned.
             If warn_main is -1 (-Wno-main) we don't want to be warned.  */
          if (! warn_main)
            pedwarn_with_decl (fndecl, "return type of `%s' is not `int'");
        }
      else
        {
#ifdef DEFAULT_MAIN_RETURN
          /* Make it so that `main' always returns success by default.  */
          DEFAULT_MAIN_RETURN;
#else
          if (flag_isoc99)
            c_expand_return (integer_zero_node);
#endif
        }
    }
  
  finish_fname_decls ();

  /* Tie off the statement tree for this function.  */
  finish_stmt_tree (&DECL_SAVED_TREE (fndecl));

  /* Complain if there's just no return statement.  */
  if (warn_return_type
      && TREE_CODE (TREE_TYPE (TREE_TYPE (fndecl))) != VOID_TYPE
      && !current_function_returns_value && !current_function_returns_null
      /* Don't complain if we abort.  */
      && !current_function_returns_abnormally
      /* Don't warn for main().  */
      && !MAIN_NAME_P (DECL_NAME (fndecl))
      /* Or if they didn't actually specify a return type.  */
      && !C_FUNCTION_IMPLICIT_INT (fndecl)
      /* Normally, with -Wreturn-type, flow will complain.  Unless we're an
         inline function, as we might never be compiled separately.  */
      && DECL_INLINE (fndecl))
    warning ("no return statement in function returning non-void");

  /* Clear out memory we no longer need.  */
  free_after_parsing (cfun);
  /* Since we never call rest_of_compilation, we never clear
     CFUN.  Do so explicitly.  */
  free_after_compilation (cfun);
  cfun = NULL;

  if (flag_unit_at_a_time && can_defer_p)
    {
      cgraph_finalize_function (fndecl, DECL_SAVED_TREE (fndecl));
      current_function_decl = NULL;
      return;
    }

  if (! nested)
    {
      /* Function is parsed.
         Generate RTL for the body of this function or defer
         it for later expansion.  */
      int uninlinable = 1;

      /* There's no reason to do any of the work here if we're only doing
         semantic analysis; this code just generates RTL.  */
      if (flag_syntax_only)
        {
          current_function_decl = NULL;
          DECL_SAVED_TREE (fndecl) = NULL_TREE;
          return;
        }

      if (flag_inline_trees)
        {
          /* First, cache whether the current function is inlinable.  Some
             predicates depend on cfun and current_function_decl to
             function completely.  */
          timevar_push (TV_INTEGRATION);
          uninlinable = ! tree_inlinable_function_p (fndecl, 0);

          if (can_defer_p
              /* We defer functions marked inline *even if* the function
                 itself is not inlinable.  This is because we don't yet
                 know if the function will actually be used; we may be
                 able to avoid emitting it entirely.  */
              && (! uninlinable || DECL_DECLARED_INLINE_P (fndecl))
              /* Save function tree for inlining.  Should return 0 if the
                 language does not support function deferring or the
                 function could not be deferred.  */
              && defer_fn (fndecl))
            {
              /* Let the back-end know that this function exists.  */
              (*debug_hooks->deferred_inline_function) (fndecl);
              timevar_pop (TV_INTEGRATION);
              current_function_decl = NULL;
              return;
            }
          
          /* Then, inline any functions called in it.  */
          optimize_inline_calls (fndecl);
          timevar_pop (TV_INTEGRATION);
        }

      c_expand_body (fndecl);

      /* Keep the function body if it's needed for inlining or dumping.  */
      if (uninlinable && !dump_enabled_p (TDI_all))
        {
          /* Allow the body of the function to be garbage collected.  */
          DECL_SAVED_TREE (fndecl) = NULL_TREE;
        }

      /* Let the error reporting routines know that we're outside a
         function.  For a nested function, this value is used in
         c_pop_function_context and then reset via pop_function_context.  */
      current_function_decl = NULL;
    }
}

/* Generate the RTL for a deferred function FNDECL.  */

void
c_expand_deferred_function (fndecl)
     tree fndecl;
{
  /* DECL_INLINE or DECL_RESULT might got cleared after the inline
     function was deferred, e.g. in duplicate_decls.  */
  if (DECL_INLINE (fndecl) && DECL_RESULT (fndecl))
    {
      if (flag_inline_trees)
        {
          timevar_push (TV_INTEGRATION);
          optimize_inline_calls (fndecl);
          timevar_pop (TV_INTEGRATION);
        }
      c_expand_body (fndecl);
      current_function_decl = NULL;
    }
}

/* Called to move the SAVE_EXPRs for parameter declarations in a
   nested function into the nested function.  DATA is really the
   nested FUNCTION_DECL.  */

static tree
set_save_expr_context (tree *tp, 
                       int *walk_subtrees,
                       void *data)
{
  if (TREE_CODE (*tp) == SAVE_EXPR && !SAVE_EXPR_CONTEXT (*tp))
    SAVE_EXPR_CONTEXT (*tp) = (tree) data;
  /* Do not walk back into the SAVE_EXPR_CONTEXT; that will cause
     circularity.  */
  else if (DECL_P (*tp))
    *walk_subtrees = 0;

  return NULL_TREE;
}

/* Generate the RTL for the body of FNDECL.  If NESTED_P is nonzero,
   then we are already in the process of generating RTL for another
   function.  If can_defer_p is zero, we won't attempt to defer the
   generation of RTL.  */

static void
c_expand_body_1 (fndecl, nested_p)
     tree fndecl;
     int nested_p;
{
  timevar_push (TV_EXPAND);

  if (nested_p)
    {
      /* Make sure that we will evaluate variable-sized types involved
         in our function's type.  */
      expand_pending_sizes (DECL_LANG_SPECIFIC (fndecl)->pending_sizes);
      /* Squirrel away our current state.  */
      push_function_context ();
    }

  /* Initialize the RTL code for the function.  */
  current_function_decl = fndecl;
  input_location = DECL_SOURCE_LOCATION (fndecl);
  init_function_start (fndecl, input_filename, DECL_SOURCE_LINE (fndecl));

  /* This function is being processed in whole-function mode.  */
  cfun->x_whole_function_mode_p = 1;

  /* Even though we're inside a function body, we still don't want to
     call expand_expr to calculate the size of a variable-sized array.
     We haven't necessarily assigned RTL to all variables yet, so it's
     not safe to try to expand expressions involving them.  */
  immediate_size_expand = 0;
  cfun->x_dont_save_pending_sizes_p = 1;

  /* Set up parameters and prepare for return, for the function.  */
  expand_function_start (fndecl, 0);

  /* If the function has a variably modified type, there may be
     SAVE_EXPRs in the parameter types.  Their context must be set to
     refer to this function; they cannot be expanded in the containing
     function.  */
  if (decl_function_context (fndecl)
      && variably_modified_type_p (TREE_TYPE (fndecl)))
    walk_tree (&TREE_TYPE (fndecl), set_save_expr_context, fndecl,
               NULL);
             
  /* If this function is `main', emit a call to `__main'
     to run global initializers, etc.  */
  if (DECL_NAME (fndecl)
      && MAIN_NAME_P (DECL_NAME (fndecl))
      && DECL_CONTEXT (fndecl) == NULL_TREE)
    expand_main_function ();

  /* Generate the RTL for this function.  */
  expand_stmt (DECL_SAVED_TREE (fndecl));

  /* We hard-wired immediate_size_expand to zero above.
     expand_function_end will decrement this variable.  So, we set the
     variable to one here, so that after the decrement it will remain
     zero.  */
  immediate_size_expand = 1;

  /* Allow language dialects to perform special processing.  */
  if (lang_expand_function_end)
    (*lang_expand_function_end) ();

  /* Generate rtl for function exit.  */
  expand_function_end (input_filename, input_line, 0);

  /* If this is a nested function, protect the local variables in the stack
     above us from being collected while we're compiling this function.  */
  if (nested_p)
    ggc_push_context ();

  /* Run the optimizers and output the assembler code for this function.  */
  rest_of_compilation (fndecl);

  /* Undo the GC context switch.  */
  if (nested_p)
    ggc_pop_context ();

  /* With just -Wextra, complain only if function returns both with
     and without a value.  */
  if (extra_warnings
      && current_function_returns_value
      && current_function_returns_null)
    warning ("this function may return with or without a value");

  /* If requested, warn about function definitions where the function will
     return a value (usually of some struct or union type) which itself will
     take up a lot of stack space.  */

  if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
    {
      tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));

      if (ret_type && TYPE_SIZE_UNIT (ret_type)
          && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
          && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
                                   larger_than_size))
        {
          unsigned int size_as_int
            = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));

          if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
            warning_with_decl (fndecl,
                               "size of return value of `%s' is %u bytes",
                               size_as_int);
          else
            warning_with_decl (fndecl,
                               "size of return value of `%s' is larger than %d bytes",
                               larger_than_size);
        }
    }

  if (DECL_SAVED_INSNS (fndecl) == 0 && ! nested_p
      && ! flag_inline_trees)
    {
      /* Stop pointing to the local nodes about to be freed.
         But DECL_INITIAL must remain nonzero so we know this
         was an actual function definition.
         For a nested function, this is done in c_pop_function_context.
         If rest_of_compilation set this to 0, leave it 0.  */
      if (DECL_INITIAL (fndecl) != 0)
        DECL_INITIAL (fndecl) = error_mark_node;

      DECL_ARGUMENTS (fndecl) = 0;
    }

  if (DECL_STATIC_CONSTRUCTOR (fndecl))
    {
      if (targetm.have_ctors_dtors)
        (* targetm.asm_out.constructor) (XEXP (DECL_RTL (fndecl), 0),
                                         DEFAULT_INIT_PRIORITY);
      else
        static_ctors = tree_cons (NULL_TREE, fndecl, static_ctors);
    }

  if (DECL_STATIC_DESTRUCTOR (fndecl))
    {
      if (targetm.have_ctors_dtors)
        (* targetm.asm_out.destructor) (XEXP (DECL_RTL (fndecl), 0),
                                        DEFAULT_INIT_PRIORITY);
      else
        static_dtors = tree_cons (NULL_TREE, fndecl, static_dtors);
    }

  if (nested_p)
    /* Return to the enclosing function.  */
    pop_function_context ();
  timevar_pop (TV_EXPAND);
}

/* Like c_expand_body_1 but only for unnested functions.  */

void
c_expand_body (fndecl)
     tree fndecl;
{
  c_expand_body_1 (fndecl, 0);
}
\f
/* Check the declarations given in a for-loop for satisfying the C99
   constraints.  */
void
check_for_loop_decls ()
{
  tree t;

  if (!flag_isoc99)
    {
      /* If we get here, declarations have been used in a for loop without
         the C99 for loop scope.  This doesn't make much sense, so don't
         allow it.  */
      error ("`for' loop initial declaration used outside C99 mode");
      return;
    }
  /* C99 subclause 6.8.5 paragraph 3:

       [#3]  The  declaration  part  of  a for statement shall only
       declare identifiers for objects having storage class auto or
       register.

     It isn't clear whether, in this sentence, "identifiers" binds to
     "shall only declare" or to "objects" - that is, whether all identifiers
     declared must be identifiers for objects, or whether the restriction
     only applies to those that are.  (A question on this in comp.std.c
     in November 2000 received no answer.)  We implement the strictest
     interpretation, to avoid creating an extension which later causes
     problems.  */

  for (t = gettags (); t; t = TREE_CHAIN (t))
    {
      if (TREE_PURPOSE (t) != 0)
        {
          enum tree_code code = TREE_CODE (TREE_VALUE (t));
          
          if (code == RECORD_TYPE)
            error ("`struct %s' declared in `for' loop initial declaration",
                   IDENTIFIER_POINTER (TREE_PURPOSE (t)));
          else if (code == UNION_TYPE)
            error ("`union %s' declared in `for' loop initial declaration",
                   IDENTIFIER_POINTER (TREE_PURPOSE (t)));
          else
            error ("`enum %s' declared in `for' loop initial declaration",
                   IDENTIFIER_POINTER (TREE_PURPOSE (t)));
        }
    }

  for (t = getdecls (); t; t = TREE_CHAIN (t))
    {
      if (TREE_CODE (t) != VAR_DECL && DECL_NAME (t))
        error_with_decl (t, "declaration of non-variable `%s' in `for' loop initial declaration");
      else if (TREE_STATIC (t))
        error_with_decl (t, "declaration of static variable `%s' in `for' loop initial declaration");
      else if (DECL_EXTERNAL (t))
        error_with_decl (t, "declaration of `extern' variable `%s' in `for' loop initial declaration");
    }
}
\f
/* Save and restore the variables in this file and elsewhere
   that keep track of the progress of compilation of the current function.
   Used for nested functions.  */

struct language_function GTY(())
{
  struct c_language_function base;
  tree named_labels;
  tree shadowed_labels;
  int returns_value;
  int returns_null;
  int returns_abnormally;
  int warn_about_return_type;
  int extern_inline;
  struct binding_level *binding_level;
};

/* Save and reinitialize the variables
   used during compilation of a C function.  */

void
c_push_function_context (f)
     struct function *f;
{
  struct language_function *p;
  p = ((struct language_function *)
       ggc_alloc (sizeof (struct language_function)));
  f->language = p;

  p->base.x_stmt_tree = c_stmt_tree;
  p->base.x_scope_stmt_stack = c_scope_stmt_stack;
  p->named_labels = named_labels;
  p->shadowed_labels = shadowed_labels;
  p->returns_value = current_function_returns_value;
  p->returns_null = current_function_returns_null;
  p->returns_abnormally = current_function_returns_abnormally;
  p->warn_about_return_type = warn_about_return_type;
  p->extern_inline = current_extern_inline;
  p->binding_level = current_binding_level;
}

/* Restore the variables used during compilation of a C function.  */

void
c_pop_function_context (f)
     struct function *f;
{
  struct language_function *p = f->language;
  tree link;

  /* Bring back all the labels that were shadowed.  */
  for (link = shadowed_labels; link; link = TREE_CHAIN (link))
    if (DECL_NAME (TREE_VALUE (link)) != 0)
      IDENTIFIER_LABEL_VALUE (DECL_NAME (TREE_VALUE (link)))
        = TREE_VALUE (link);

  if (DECL_SAVED_INSNS (current_function_decl) == 0
      && DECL_SAVED_TREE (current_function_decl) == NULL_TREE)
    {
      /* Stop pointing to the local nodes about to be freed.  */
      /* But DECL_INITIAL must remain nonzero so we know this
         was an actual function definition.  */
      DECL_INITIAL (current_function_decl) = error_mark_node;
      DECL_ARGUMENTS (current_function_decl) = 0;
    }

  c_stmt_tree = p->base.x_stmt_tree;
  c_scope_stmt_stack = p->base.x_scope_stmt_stack;
  named_labels = p->named_labels;
  shadowed_labels = p->shadowed_labels;
  current_function_returns_value = p->returns_value;
  current_function_returns_null = p->returns_null;
  current_function_returns_abnormally = p->returns_abnormally;
  warn_about_return_type = p->warn_about_return_type;
  current_extern_inline = p->extern_inline;
  current_binding_level = p->binding_level;

  f->language = NULL;
}

/* Copy the DECL_LANG_SPECIFIC data associated with DECL.  */

void
c_dup_lang_specific_decl (decl)
     tree decl;
{
  struct lang_decl *ld;

  if (!DECL_LANG_SPECIFIC (decl))
    return;

  ld = (struct lang_decl *) ggc_alloc (sizeof (struct lang_decl));
  memcpy ((char *) ld, (char *) DECL_LANG_SPECIFIC (decl),
          sizeof (struct lang_decl));
  DECL_LANG_SPECIFIC (decl) = ld;
}

/* The functions below are required for functionality of doing
   function at once processing in the C front end. Currently these
   functions are not called from anywhere in the C front end, but as
   these changes continue, that will change.  */

/* Returns nonzero if the current statement is a full expression,
   i.e. temporaries created during that statement should be destroyed
   at the end of the statement.  */

int
stmts_are_full_exprs_p ()
{
  return 0;
}

/* Returns the stmt_tree (if any) to which statements are currently
   being added.  If there is no active statement-tree, NULL is
   returned.  */

stmt_tree
current_stmt_tree ()
{
  return &c_stmt_tree;
}

/* Returns the stack of SCOPE_STMTs for the current function.  */

tree *
current_scope_stmt_stack ()
{
  return &c_scope_stmt_stack;
}

/* Nonzero if TYPE is an anonymous union or struct type.  Always 0 in
   C.  */

int
anon_aggr_type_p (node)
     tree node ATTRIBUTE_UNUSED;
{
  return 0;
}

/* Dummy function in place of callback used by C++.  */

void
extract_interface_info ()
{
}

/* Return a new COMPOUND_STMT, after adding it to the current
   statement tree.  */

tree
c_begin_compound_stmt ()
{
  tree stmt;

  /* Create the COMPOUND_STMT.  */
  stmt = add_stmt (build_stmt (COMPOUND_STMT, NULL_TREE));

  return stmt;
}

/* Expand T (a DECL_STMT) if it declares an entity not handled by the
   common code.  */

void
c_expand_decl_stmt (t)
     tree t;
{
  tree decl = DECL_STMT_DECL (t);

  /* Expand nested functions.  */
  if (TREE_CODE (decl) == FUNCTION_DECL
      && DECL_CONTEXT (decl) == current_function_decl
      && DECL_SAVED_TREE (decl))
    c_expand_body_1 (decl, 1);
}

/* Return the global value of T as a symbol.  */

tree
identifier_global_value (t)
     tree t;
{
  tree decl = IDENTIFIER_SYMBOL_VALUE (t);
  if (decl == 0 || DECL_CONTEXT (decl) == 0)
    return decl;

  /* Shadowed by something else; find the true global value.  */
  for (decl = global_binding_level->names; decl; decl = TREE_CHAIN (decl))
    if (DECL_NAME (decl) == t)
      return decl;

  /* Only local values for this decl.  */
  return 0;
}

/* Record a builtin type for C.  If NAME is non-NULL, it is the name used;
   otherwise the name is found in ridpointers from RID_INDEX.  */

void
record_builtin_type (rid_index, name, type)
     enum rid rid_index;
     const char *name;
     tree type;
{
  tree id;
  if (name == 0)
    id = ridpointers[(int) rid_index];
  else
    id = get_identifier (name);
  pushdecl (build_decl (TYPE_DECL, id, type));
}

/* Build the void_list_node (void_type_node having been created).  */
tree
build_void_list_node ()
{
  tree t = build_tree_list (NULL_TREE, void_type_node);
  return t;
}

/* Return something to represent absolute declarators containing a *.
   TARGET is the absolute declarator that the * contains.
   TYPE_QUALS_ATTRS is a list of modifiers such as const or volatile
   to apply to the pointer type, represented as identifiers, possible mixed
   with attributes.

   We return an INDIRECT_REF whose "contents" are TARGET (inside a TREE_LIST,
   if attributes are present) and whose type is the modifier list.  */

tree
make_pointer_declarator (type_quals_attrs, target)
     tree type_quals_attrs, target;
{
  tree quals, attrs;
  tree itarget = target;
  split_specs_attrs (type_quals_attrs, &quals, &attrs);
  if (attrs != NULL_TREE)
    itarget = tree_cons (attrs, target, NULL_TREE);
  return build1 (INDIRECT_REF, quals, itarget);
}

#include "gt-c-decl.h"