PR c++/19253

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

/* C++ Parser.
   Copyright (C) 2000, 2001, 2002, 2003, 2004,
   2005  Free Software Foundation, Inc.
   Written by Mark Mitchell <mark@codesourcery.com>.

   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, 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "dyn-string.h"
#include "varray.h"
#include "cpplib.h"
#include "tree.h"
#include "cp-tree.h"
#include "c-pragma.h"
#include "decl.h"
#include "flags.h"
#include "diagnostic.h"
#include "toplev.h"
#include "output.h"
#include "target.h"
#include "c-common.h"

\f
/* The lexer.  */

/* The cp_lexer_* routines mediate between the lexer proper (in libcpp
   and c-lex.c) and the C++ parser.  */

/* A C++ token.  */

typedef struct cp_token GTY (())
{
  /* The kind of token.  */
  ENUM_BITFIELD (cpp_ttype) type : 8;
  /* If this token is a keyword, this value indicates which keyword.
     Otherwise, this value is RID_MAX.  */
  ENUM_BITFIELD (rid) keyword : 8;
  /* Token flags.  */
  unsigned char flags;
  /* True if this token is from a system header.  */
  BOOL_BITFIELD in_system_header : 1;
  /* True if this token is from a context where it is implicitly extern "C" */
  BOOL_BITFIELD implicit_extern_c : 1;
  /* The value associated with this token, if any.  */
  tree value;
  /* The location at which this token was found.  */
  location_t location;
} cp_token;

/* We use a stack of token pointer for saving token sets.  */
typedef struct cp_token *cp_token_position;
DEF_VEC_P (cp_token_position);
DEF_VEC_ALLOC_P (cp_token_position,heap);

static const cp_token eof_token =
{
  CPP_EOF, RID_MAX, 0, 0, 0, NULL_TREE,
#if USE_MAPPED_LOCATION
  0
#else
  {0, 0}
#endif
};

/* The cp_lexer structure represents the C++ lexer.  It is responsible
   for managing the token stream from the preprocessor and supplying
   it to the parser.  Tokens are never added to the cp_lexer after
   it is created.  */

typedef struct cp_lexer GTY (())
{
  /* The memory allocated for the buffer.  NULL if this lexer does not
     own the token buffer.  */
  cp_token * GTY ((length ("%h.buffer_length"))) buffer;
  /* If the lexer owns the buffer, this is the number of tokens in the
     buffer.  */
  size_t buffer_length;

  /* A pointer just past the last available token.  The tokens
     in this lexer are [buffer, last_token).  */
  cp_token_position GTY ((skip)) last_token;

  /* The next available token.  If NEXT_TOKEN is &eof_token, then there are
     no more available tokens.  */
  cp_token_position GTY ((skip)) next_token;

  /* A stack indicating positions at which cp_lexer_save_tokens was
     called.  The top entry is the most recent position at which we
     began saving tokens.  If the stack is non-empty, we are saving
     tokens.  */
  VEC(cp_token_position,heap) *GTY ((skip)) saved_tokens;

  /* True if we should output debugging information.  */
  bool debugging_p;

  /* The next lexer in a linked list of lexers.  */
  struct cp_lexer *next;
} cp_lexer;

/* cp_token_cache is a range of tokens.  There is no need to represent
   allocate heap memory for it, since tokens are never removed from the
   lexer's array.  There is also no need for the GC to walk through
   a cp_token_cache, since everything in here is referenced through
   a lexer.  */

typedef struct cp_token_cache GTY(())
{
  /* The beginning of the token range.  */
  cp_token * GTY((skip)) first;

  /* Points immediately after the last token in the range.  */
  cp_token * GTY ((skip)) last;
} cp_token_cache;

/* Prototypes.  */

static cp_lexer *cp_lexer_new_main
  (void);
static cp_lexer *cp_lexer_new_from_tokens
  (cp_token_cache *tokens);
static void cp_lexer_destroy
  (cp_lexer *);
static int cp_lexer_saving_tokens
  (const cp_lexer *);
static cp_token_position cp_lexer_token_position
  (cp_lexer *, bool);
static cp_token *cp_lexer_token_at
  (cp_lexer *, cp_token_position);
static void cp_lexer_get_preprocessor_token
  (cp_lexer *, cp_token *);
static inline cp_token *cp_lexer_peek_token
  (cp_lexer *);
static cp_token *cp_lexer_peek_nth_token
  (cp_lexer *, size_t);
static inline bool cp_lexer_next_token_is
  (cp_lexer *, enum cpp_ttype);
static bool cp_lexer_next_token_is_not
  (cp_lexer *, enum cpp_ttype);
static bool cp_lexer_next_token_is_keyword
  (cp_lexer *, enum rid);
static cp_token *cp_lexer_consume_token
  (cp_lexer *);
static void cp_lexer_purge_token
  (cp_lexer *);
static void cp_lexer_purge_tokens_after
  (cp_lexer *, cp_token_position);
static void cp_lexer_handle_pragma
  (cp_lexer *);
static void cp_lexer_save_tokens
  (cp_lexer *);
static void cp_lexer_commit_tokens
  (cp_lexer *);
static void cp_lexer_rollback_tokens
  (cp_lexer *);
#ifdef ENABLE_CHECKING
static void cp_lexer_print_token
  (FILE *, cp_token *);
static inline bool cp_lexer_debugging_p
  (cp_lexer *);
static void cp_lexer_start_debugging
  (cp_lexer *) ATTRIBUTE_UNUSED;
static void cp_lexer_stop_debugging
  (cp_lexer *) ATTRIBUTE_UNUSED;
#else
/* If we define cp_lexer_debug_stream to NULL it will provoke warnings
   about passing NULL to functions that require non-NULL arguments
   (fputs, fprintf).  It will never be used, so all we need is a value
   of the right type that's guaranteed not to be NULL.  */
#define cp_lexer_debug_stream stdout
#define cp_lexer_print_token(str, tok) (void) 0
#define cp_lexer_debugging_p(lexer) 0
#endif /* ENABLE_CHECKING */

static cp_token_cache *cp_token_cache_new
  (cp_token *, cp_token *);

/* Manifest constants.  */
#define CP_LEXER_BUFFER_SIZE 10000
#define CP_SAVED_TOKEN_STACK 5

/* A token type for keywords, as opposed to ordinary identifiers.  */
#define CPP_KEYWORD ((enum cpp_ttype) (N_TTYPES + 1))

/* A token type for template-ids.  If a template-id is processed while
   parsing tentatively, it is replaced with a CPP_TEMPLATE_ID token;
   the value of the CPP_TEMPLATE_ID is whatever was returned by
   cp_parser_template_id.  */
#define CPP_TEMPLATE_ID ((enum cpp_ttype) (CPP_KEYWORD + 1))

/* A token type for nested-name-specifiers.  If a
   nested-name-specifier is processed while parsing tentatively, it is
   replaced with a CPP_NESTED_NAME_SPECIFIER token; the value of the
   CPP_NESTED_NAME_SPECIFIER is whatever was returned by
   cp_parser_nested_name_specifier_opt.  */
#define CPP_NESTED_NAME_SPECIFIER ((enum cpp_ttype) (CPP_TEMPLATE_ID + 1))

/* A token type for tokens that are not tokens at all; these are used
   to represent slots in the array where there used to be a token
   that has now been deleted.  */
#define CPP_PURGED ((enum cpp_ttype) (CPP_NESTED_NAME_SPECIFIER + 1))

/* The number of token types, including C++-specific ones.  */
#define N_CP_TTYPES ((int) (CPP_PURGED + 1))

/* Variables.  */

#ifdef ENABLE_CHECKING
/* The stream to which debugging output should be written.  */
static FILE *cp_lexer_debug_stream;
#endif /* ENABLE_CHECKING */

/* Create a new main C++ lexer, the lexer that gets tokens from the
   preprocessor.  */

static cp_lexer *
cp_lexer_new_main (void)
{
  cp_token first_token;
  cp_lexer *lexer;
  cp_token *pos;
  size_t alloc;
  size_t space;
  cp_token *buffer;

  /* It's possible that lexing the first token will load a PCH file,
     which is a GC collection point.  So we have to grab the first
     token before allocating any memory.  Pragmas must not be deferred
     as -fpch-preprocess can generate a pragma to load the PCH file in
     the preprocessed output used by -save-temps.  */
  cp_lexer_get_preprocessor_token (NULL, &first_token);

  /* Tell cpplib we want CPP_PRAGMA tokens.  */
  cpp_get_options (parse_in)->defer_pragmas = true;

  /* Tell c_lex not to merge string constants.  */
  c_lex_return_raw_strings = true;

  c_common_no_more_pch ();

  /* Allocate the memory.  */
  lexer = GGC_CNEW (cp_lexer);

#ifdef ENABLE_CHECKING
  /* Initially we are not debugging.  */
  lexer->debugging_p = false;
#endif /* ENABLE_CHECKING */
  lexer->saved_tokens = VEC_alloc (cp_token_position, heap,
                                   CP_SAVED_TOKEN_STACK);

  /* Create the buffer.  */
  alloc = CP_LEXER_BUFFER_SIZE;
  buffer = ggc_alloc (alloc * sizeof (cp_token));

  /* Put the first token in the buffer.  */
  space = alloc;
  pos = buffer;
  *pos = first_token;

  /* Get the remaining tokens from the preprocessor.  */
  while (pos->type != CPP_EOF)
    {
      pos++;
      if (!--space)
        {
          space = alloc;
          alloc *= 2;
          buffer = ggc_realloc (buffer, alloc * sizeof (cp_token));
          pos = buffer + space;
        }
      cp_lexer_get_preprocessor_token (lexer, pos);
    }
  lexer->buffer = buffer;
  lexer->buffer_length = alloc - space;
  lexer->last_token = pos;
  lexer->next_token = lexer->buffer_length ? buffer : (cp_token *)&eof_token;

  /* Pragma processing (via cpp_handle_deferred_pragma) may result in
     direct calls to c_lex.  Those callers all expect c_lex to do
     string constant concatenation.  */
  c_lex_return_raw_strings = false;

  gcc_assert (lexer->next_token->type != CPP_PURGED);
  return lexer;
}

/* Create a new lexer whose token stream is primed with the tokens in
   CACHE.  When these tokens are exhausted, no new tokens will be read.  */

static cp_lexer *
cp_lexer_new_from_tokens (cp_token_cache *cache)
{
  cp_token *first = cache->first;
  cp_token *last = cache->last;
  cp_lexer *lexer = GGC_CNEW (cp_lexer);

  /* We do not own the buffer.  */
  lexer->buffer = NULL;
  lexer->buffer_length = 0;
  lexer->next_token = first == last ? (cp_token *)&eof_token : first;
  lexer->last_token = last;

  lexer->saved_tokens = VEC_alloc (cp_token_position, heap,
                                   CP_SAVED_TOKEN_STACK);

#ifdef ENABLE_CHECKING
  /* Initially we are not debugging.  */
  lexer->debugging_p = false;
#endif

  gcc_assert (lexer->next_token->type != CPP_PURGED);
  return lexer;
}

/* Frees all resources associated with LEXER.  */

static void
cp_lexer_destroy (cp_lexer *lexer)
{
  if (lexer->buffer)
    ggc_free (lexer->buffer);
  VEC_free (cp_token_position, heap, lexer->saved_tokens);
  ggc_free (lexer);
}

/* Returns nonzero if debugging information should be output.  */

#ifdef ENABLE_CHECKING

static inline bool
cp_lexer_debugging_p (cp_lexer *lexer)
{
  return lexer->debugging_p;
}

#endif /* ENABLE_CHECKING */

static inline cp_token_position
cp_lexer_token_position (cp_lexer *lexer, bool previous_p)
{
  gcc_assert (!previous_p || lexer->next_token != &eof_token);

  return lexer->next_token - previous_p;
}

static inline cp_token *
cp_lexer_token_at (cp_lexer *lexer ATTRIBUTE_UNUSED, cp_token_position pos)
{
  return pos;
}

/* nonzero if we are presently saving tokens.  */

static inline int
cp_lexer_saving_tokens (const cp_lexer* lexer)
{
  return VEC_length (cp_token_position, lexer->saved_tokens) != 0;
}

/* Store the next token from the preprocessor in *TOKEN.  Return true
   if we reach EOF.  */

static void
cp_lexer_get_preprocessor_token (cp_lexer *lexer ATTRIBUTE_UNUSED ,
                                 cp_token *token)
{
  static int is_extern_c = 0;

   /* Get a new token from the preprocessor.  */
  token->type
    = c_lex_with_flags (&token->value, &token->location, &token->flags);
  token->in_system_header = in_system_header;

  /* On some systems, some header files are surrounded by an
     implicit extern "C" block.  Set a flag in the token if it
     comes from such a header.  */
  is_extern_c += pending_lang_change;
  pending_lang_change = 0;
  token->implicit_extern_c = is_extern_c > 0;

  /* Check to see if this token is a keyword.  */
  if (token->type == CPP_NAME
      && C_IS_RESERVED_WORD (token->value))
    {
      /* Mark this token as a keyword.  */
      token->type = CPP_KEYWORD;
      /* Record which keyword.  */
      token->keyword = C_RID_CODE (token->value);
      /* Update the value.  Some keywords are mapped to particular
         entities, rather than simply having the value of the
         corresponding IDENTIFIER_NODE.  For example, `__const' is
         mapped to `const'.  */
      token->value = ridpointers[token->keyword];
    }
  /* Handle Objective-C++ keywords.  */
  else if (token->type == CPP_AT_NAME)
    {
      token->type = CPP_KEYWORD;
      switch (C_RID_CODE (token->value))
        {
        /* Map 'class' to '@class', 'private' to '@private', etc.  */
        case RID_CLASS: token->keyword = RID_AT_CLASS; break;
        case RID_PRIVATE: token->keyword = RID_AT_PRIVATE; break;
        case RID_PROTECTED: token->keyword = RID_AT_PROTECTED; break;
        case RID_PUBLIC: token->keyword = RID_AT_PUBLIC; break;
        case RID_THROW: token->keyword = RID_AT_THROW; break;
        case RID_TRY: token->keyword = RID_AT_TRY; break;
        case RID_CATCH: token->keyword = RID_AT_CATCH; break;
        default: token->keyword = C_RID_CODE (token->value);
        }
    }
  else
    token->keyword = RID_MAX;
}

/* Update the globals input_location and in_system_header from TOKEN.  */
static inline void
cp_lexer_set_source_position_from_token (cp_token *token)
{
  if (token->type != CPP_EOF)
    {
      input_location = token->location;
      in_system_header = token->in_system_header;
    }
}

/* Return a pointer to the next token in the token stream, but do not
   consume it.  */

static inline cp_token *
cp_lexer_peek_token (cp_lexer *lexer)
{
  if (cp_lexer_debugging_p (lexer))
    {
      fputs ("cp_lexer: peeking at token: ", cp_lexer_debug_stream);
      cp_lexer_print_token (cp_lexer_debug_stream, lexer->next_token);
      putc ('\n', cp_lexer_debug_stream);
    }
  return lexer->next_token;
}

/* Return true if the next token has the indicated TYPE.  */

static inline bool
cp_lexer_next_token_is (cp_lexer* lexer, enum cpp_ttype type)
{
  return cp_lexer_peek_token (lexer)->type == type;
}

/* Return true if the next token does not have the indicated TYPE.  */

static inline bool
cp_lexer_next_token_is_not (cp_lexer* lexer, enum cpp_ttype type)
{
  return !cp_lexer_next_token_is (lexer, type);
}

/* Return true if the next token is the indicated KEYWORD.  */

static inline bool
cp_lexer_next_token_is_keyword (cp_lexer* lexer, enum rid keyword)
{
  cp_token *token;

  /* Peek at the next token.  */
  token = cp_lexer_peek_token (lexer);
  /* Check to see if it is the indicated keyword.  */
  return token->keyword == keyword;
}

/* Return a pointer to the Nth token in the token stream.  If N is 1,
   then this is precisely equivalent to cp_lexer_peek_token (except
   that it is not inline).  One would like to disallow that case, but
   there is one case (cp_parser_nth_token_starts_template_id) where
   the caller passes a variable for N and it might be 1.  */

static cp_token *
cp_lexer_peek_nth_token (cp_lexer* lexer, size_t n)
{
  cp_token *token;

  /* N is 1-based, not zero-based.  */
  gcc_assert (n > 0);
  
  if (cp_lexer_debugging_p (lexer))
    fprintf (cp_lexer_debug_stream,
             "cp_lexer: peeking ahead %ld at token: ", (long)n);

  --n;
  token = lexer->next_token;
  gcc_assert (!n || token != &eof_token);
  while (n != 0)
    {
      ++token;
      if (token == lexer->last_token)
        {
          token = (cp_token *)&eof_token;
          break;
        }

      if (token->type != CPP_PURGED)
        --n;
    }

  if (cp_lexer_debugging_p (lexer))
    {
      cp_lexer_print_token (cp_lexer_debug_stream, token);
      putc ('\n', cp_lexer_debug_stream);
    }

  return token;
}

/* Return the next token, and advance the lexer's next_token pointer
   to point to the next non-purged token.  */

static cp_token *
cp_lexer_consume_token (cp_lexer* lexer)
{
  cp_token *token = lexer->next_token;

  gcc_assert (token != &eof_token);

  do
    {
      lexer->next_token++;
      if (lexer->next_token == lexer->last_token)
        {
          lexer->next_token = (cp_token *)&eof_token;
          break;
        }

    }
  while (lexer->next_token->type == CPP_PURGED);

  cp_lexer_set_source_position_from_token (token);

  /* Provide debugging output.  */
  if (cp_lexer_debugging_p (lexer))
    {
      fputs ("cp_lexer: consuming token: ", cp_lexer_debug_stream);
      cp_lexer_print_token (cp_lexer_debug_stream, token);
      putc ('\n', cp_lexer_debug_stream);
    }

  return token;
}

/* Permanently remove the next token from the token stream, and
   advance the next_token pointer to refer to the next non-purged
   token.  */

static void
cp_lexer_purge_token (cp_lexer *lexer)
{
  cp_token *tok = lexer->next_token;

  gcc_assert (tok != &eof_token);
  tok->type = CPP_PURGED;
  tok->location = UNKNOWN_LOCATION;
  tok->value = NULL_TREE;
  tok->keyword = RID_MAX;

  do
    {
      tok++;
      if (tok == lexer->last_token)
        {
          tok = (cp_token *)&eof_token;
          break;
        }
    }
  while (tok->type == CPP_PURGED);
  lexer->next_token = tok;
}

/* Permanently remove all tokens after TOK, up to, but not
   including, the token that will be returned next by
   cp_lexer_peek_token.  */

static void
cp_lexer_purge_tokens_after (cp_lexer *lexer, cp_token *tok)
{
  cp_token *peek = lexer->next_token;

  if (peek == &eof_token)
    peek = lexer->last_token;

  gcc_assert (tok < peek);

  for ( tok += 1; tok != peek; tok += 1)
    {
      tok->type = CPP_PURGED;
      tok->location = UNKNOWN_LOCATION;
      tok->value = NULL_TREE;
      tok->keyword = RID_MAX;
    }
}

/* Consume and handle a pragma token.  */
static void
cp_lexer_handle_pragma (cp_lexer *lexer)
{
  cpp_string s;
  cp_token *token = cp_lexer_consume_token (lexer);
  gcc_assert (token->type == CPP_PRAGMA);
  gcc_assert (token->value);

  s.len = TREE_STRING_LENGTH (token->value);
  s.text = (const unsigned char *) TREE_STRING_POINTER (token->value);

  cpp_handle_deferred_pragma (parse_in, &s);

  /* Clearing token->value here means that we will get an ICE if we
     try to process this #pragma again (which should be impossible).  */
  token->value = NULL;
}

/* Begin saving tokens.  All tokens consumed after this point will be
   preserved.  */

static void
cp_lexer_save_tokens (cp_lexer* lexer)
{
  /* Provide debugging output.  */
  if (cp_lexer_debugging_p (lexer))
    fprintf (cp_lexer_debug_stream, "cp_lexer: saving tokens\n");

  VEC_safe_push (cp_token_position, heap,
                 lexer->saved_tokens, lexer->next_token);
}

/* Commit to the portion of the token stream most recently saved.  */

static void
cp_lexer_commit_tokens (cp_lexer* lexer)
{
  /* Provide debugging output.  */
  if (cp_lexer_debugging_p (lexer))
    fprintf (cp_lexer_debug_stream, "cp_lexer: committing tokens\n");

  VEC_pop (cp_token_position, lexer->saved_tokens);
}

/* Return all tokens saved since the last call to cp_lexer_save_tokens
   to the token stream.  Stop saving tokens.  */

static void
cp_lexer_rollback_tokens (cp_lexer* lexer)
{
  /* Provide debugging output.  */
  if (cp_lexer_debugging_p (lexer))
    fprintf (cp_lexer_debug_stream, "cp_lexer: restoring tokens\n");

  lexer->next_token = VEC_pop (cp_token_position, lexer->saved_tokens);
}

/* Print a representation of the TOKEN on the STREAM.  */

#ifdef ENABLE_CHECKING

static void
cp_lexer_print_token (FILE * stream, cp_token *token)
{
  /* We don't use cpp_type2name here because the parser defines
     a few tokens of its own.  */
  static const char *const token_names[] = {
    /* cpplib-defined token types */
#define OP(e, s) #e,
#define TK(e, s) #e,
    TTYPE_TABLE
#undef OP
#undef TK
    /* C++ parser token types - see "Manifest constants", above.  */
    "KEYWORD",
    "TEMPLATE_ID",
    "NESTED_NAME_SPECIFIER",
    "PURGED"
  };

  /* If we have a name for the token, print it out.  Otherwise, we
     simply give the numeric code.  */
  gcc_assert (token->type < ARRAY_SIZE(token_names));
  fputs (token_names[token->type], stream);

  /* For some tokens, print the associated data.  */
  switch (token->type)
    {
    case CPP_KEYWORD:
      /* Some keywords have a value that is not an IDENTIFIER_NODE.
         For example, `struct' is mapped to an INTEGER_CST.  */
      if (TREE_CODE (token->value) != IDENTIFIER_NODE)
        break;
      /* else fall through */
    case CPP_NAME:
      fputs (IDENTIFIER_POINTER (token->value), stream);
      break;

    case CPP_STRING:
    case CPP_WSTRING:
    case CPP_PRAGMA:
      fprintf (stream, " \"%s\"", TREE_STRING_POINTER (token->value));
      break;

    default:
      break;
    }
}

/* Start emitting debugging information.  */

static void
cp_lexer_start_debugging (cp_lexer* lexer)
{
  lexer->debugging_p = true;
}

/* Stop emitting debugging information.  */

static void
cp_lexer_stop_debugging (cp_lexer* lexer)
{
  lexer->debugging_p = false;
}

#endif /* ENABLE_CHECKING */

/* Create a new cp_token_cache, representing a range of tokens.  */

static cp_token_cache *
cp_token_cache_new (cp_token *first, cp_token *last)
{
  cp_token_cache *cache = GGC_NEW (cp_token_cache);
  cache->first = first;
  cache->last = last;
  return cache;
}

\f
/* Decl-specifiers.  */

static void clear_decl_specs
  (cp_decl_specifier_seq *);

/* Set *DECL_SPECS to represent an empty decl-specifier-seq.  */

static void
clear_decl_specs (cp_decl_specifier_seq *decl_specs)
{
  memset (decl_specs, 0, sizeof (cp_decl_specifier_seq));
}

/* Declarators.  */

/* Nothing other than the parser should be creating declarators;
   declarators are a semi-syntactic representation of C++ entities.
   Other parts of the front end that need to create entities (like
   VAR_DECLs or FUNCTION_DECLs) should do that directly.  */

static cp_declarator *make_call_declarator
  (cp_declarator *, cp_parameter_declarator *, cp_cv_quals, tree);
static cp_declarator *make_array_declarator
  (cp_declarator *, tree);
static cp_declarator *make_pointer_declarator
  (cp_cv_quals, cp_declarator *);
static cp_declarator *make_reference_declarator
  (cp_cv_quals, cp_declarator *);
static cp_parameter_declarator *make_parameter_declarator
  (cp_decl_specifier_seq *, cp_declarator *, tree);
static cp_declarator *make_ptrmem_declarator
  (cp_cv_quals, tree, cp_declarator *);

cp_declarator *cp_error_declarator;

/* The obstack on which declarators and related data structures are
   allocated.  */
static struct obstack declarator_obstack;

/* Alloc BYTES from the declarator memory pool.  */

static inline void *
alloc_declarator (size_t bytes)
{
  return obstack_alloc (&declarator_obstack, bytes);
}

/* Allocate a declarator of the indicated KIND.  Clear fields that are
   common to all declarators.  */

static cp_declarator *
make_declarator (cp_declarator_kind kind)
{
  cp_declarator *declarator;

  declarator = (cp_declarator *) alloc_declarator (sizeof (cp_declarator));
  declarator->kind = kind;
  declarator->attributes = NULL_TREE;
  declarator->declarator = NULL;

  return declarator;
}

/* Make a declarator for a generalized identifier.  If non-NULL, the
   identifier is QUALIFYING_SCOPE::UNQUALIFIED_NAME; otherwise, it is
   just UNQUALIFIED_NAME.  */

static cp_declarator *
make_id_declarator (tree qualifying_scope, tree unqualified_name)
{
  cp_declarator *declarator;

  /* It is valid to write:

       class C { void f(); };
       typedef C D;
       void D::f();

     The standard is not clear about whether `typedef const C D' is
     legal; as of 2002-09-15 the committee is considering that
     question.  EDG 3.0 allows that syntax.  Therefore, we do as
     well.  */
  if (qualifying_scope && TYPE_P (qualifying_scope))
    qualifying_scope = TYPE_MAIN_VARIANT (qualifying_scope);

  declarator = make_declarator (cdk_id);
  declarator->u.id.qualifying_scope = qualifying_scope;
  declarator->u.id.unqualified_name = unqualified_name;
  declarator->u.id.sfk = sfk_none;

  return declarator;
}

/* Make a declarator for a pointer to TARGET.  CV_QUALIFIERS is a list
   of modifiers such as const or volatile to apply to the pointer
   type, represented as identifiers.  */

cp_declarator *
make_pointer_declarator (cp_cv_quals cv_qualifiers, cp_declarator *target)
{
  cp_declarator *declarator;

  declarator = make_declarator (cdk_pointer);
  declarator->declarator = target;
  declarator->u.pointer.qualifiers = cv_qualifiers;
  declarator->u.pointer.class_type = NULL_TREE;

  return declarator;
}

/* Like make_pointer_declarator -- but for references.  */

cp_declarator *
make_reference_declarator (cp_cv_quals cv_qualifiers, cp_declarator *target)
{
  cp_declarator *declarator;

  declarator = make_declarator (cdk_reference);
  declarator->declarator = target;
  declarator->u.pointer.qualifiers = cv_qualifiers;
  declarator->u.pointer.class_type = NULL_TREE;

  return declarator;
}

/* Like make_pointer_declarator -- but for a pointer to a non-static
   member of CLASS_TYPE.  */

cp_declarator *
make_ptrmem_declarator (cp_cv_quals cv_qualifiers, tree class_type,
                        cp_declarator *pointee)
{
  cp_declarator *declarator;

  declarator = make_declarator (cdk_ptrmem);
  declarator->declarator = pointee;
  declarator->u.pointer.qualifiers = cv_qualifiers;
  declarator->u.pointer.class_type = class_type;

  return declarator;
}

/* Make a declarator for the function given by TARGET, with the
   indicated PARMS.  The CV_QUALIFIERS aply to the function, as in
   "const"-qualified member function.  The EXCEPTION_SPECIFICATION
   indicates what exceptions can be thrown.  */

cp_declarator *
make_call_declarator (cp_declarator *target,
                      cp_parameter_declarator *parms,
                      cp_cv_quals cv_qualifiers,
                      tree exception_specification)
{
  cp_declarator *declarator;

  declarator = make_declarator (cdk_function);
  declarator->declarator = target;
  declarator->u.function.parameters = parms;
  declarator->u.function.qualifiers = cv_qualifiers;
  declarator->u.function.exception_specification = exception_specification;

  return declarator;
}

/* Make a declarator for an array of BOUNDS elements, each of which is
   defined by ELEMENT.  */

cp_declarator *
make_array_declarator (cp_declarator *element, tree bounds)
{
  cp_declarator *declarator;

  declarator = make_declarator (cdk_array);
  declarator->declarator = element;
  declarator->u.array.bounds = bounds;

  return declarator;
}

cp_parameter_declarator *no_parameters;

/* Create a parameter declarator with the indicated DECL_SPECIFIERS,
   DECLARATOR and DEFAULT_ARGUMENT.  */

cp_parameter_declarator *
make_parameter_declarator (cp_decl_specifier_seq *decl_specifiers,
                           cp_declarator *declarator,
                           tree default_argument)
{
  cp_parameter_declarator *parameter;

  parameter = ((cp_parameter_declarator *)
               alloc_declarator (sizeof (cp_parameter_declarator)));
  parameter->next = NULL;
  if (decl_specifiers)
    parameter->decl_specifiers = *decl_specifiers;
  else
    clear_decl_specs (&parameter->decl_specifiers);
  parameter->declarator = declarator;
  parameter->default_argument = default_argument;
  parameter->ellipsis_p = false;

  return parameter;
}

/* The parser.  */

/* Overview
   --------

   A cp_parser parses the token stream as specified by the C++
   grammar.  Its job is purely parsing, not semantic analysis.  For
   example, the parser breaks the token stream into declarators,
   expressions, statements, and other similar syntactic constructs.
   It does not check that the types of the expressions on either side
   of an assignment-statement are compatible, or that a function is
   not declared with a parameter of type `void'.

   The parser invokes routines elsewhere in the compiler to perform
   semantic analysis and to build up the abstract syntax tree for the
   code processed.

   The parser (and the template instantiation code, which is, in a
   way, a close relative of parsing) are the only parts of the
   compiler that should be calling push_scope and pop_scope, or
   related functions.  The parser (and template instantiation code)
   keeps track of what scope is presently active; everything else
   should simply honor that.  (The code that generates static
   initializers may also need to set the scope, in order to check
   access control correctly when emitting the initializers.)

   Methodology
   -----------

   The parser is of the standard recursive-descent variety.  Upcoming
   tokens in the token stream are examined in order to determine which
   production to use when parsing a non-terminal.  Some C++ constructs
   require arbitrary look ahead to disambiguate.  For example, it is
   impossible, in the general case, to tell whether a statement is an
   expression or declaration without scanning the entire statement.
   Therefore, the parser is capable of "parsing tentatively."  When the
   parser is not sure what construct comes next, it enters this mode.
   Then, while we attempt to parse the construct, the parser queues up
   error messages, rather than issuing them immediately, and saves the
   tokens it consumes.  If the construct is parsed successfully, the
   parser "commits", i.e., it issues any queued error messages and
   the tokens that were being preserved are permanently discarded.
   If, however, the construct is not parsed successfully, the parser
   rolls back its state completely so that it can resume parsing using
   a different alternative.

   Future Improvements
   -------------------

   The performance of the parser could probably be improved substantially.
   We could often eliminate the need to parse tentatively by looking ahead
   a little bit.  In some places, this approach might not entirely eliminate
   the need to parse tentatively, but it might still speed up the average
   case.  */

/* Flags that are passed to some parsing functions.  These values can
   be bitwise-ored together.  */

typedef enum cp_parser_flags
{
  /* No flags.  */
  CP_PARSER_FLAGS_NONE = 0x0,
  /* The construct is optional.  If it is not present, then no error
     should be issued.  */
  CP_PARSER_FLAGS_OPTIONAL = 0x1,
  /* When parsing a type-specifier, do not allow user-defined types.  */
  CP_PARSER_FLAGS_NO_USER_DEFINED_TYPES = 0x2
} cp_parser_flags;

/* The different kinds of declarators we want to parse.  */

typedef enum cp_parser_declarator_kind
{
  /* We want an abstract declarator.  */
  CP_PARSER_DECLARATOR_ABSTRACT,
  /* We want a named declarator.  */
  CP_PARSER_DECLARATOR_NAMED,
  /* We don't mind, but the name must be an unqualified-id.  */
  CP_PARSER_DECLARATOR_EITHER
} cp_parser_declarator_kind;

/* The precedence values used to parse binary expressions.  The minimum value
   of PREC must be 1, because zero is reserved to quickly discriminate
   binary operators from other tokens.  */

enum cp_parser_prec
{
  PREC_NOT_OPERATOR,
  PREC_LOGICAL_OR_EXPRESSION,
  PREC_LOGICAL_AND_EXPRESSION,
  PREC_INCLUSIVE_OR_EXPRESSION,
  PREC_EXCLUSIVE_OR_EXPRESSION,
  PREC_AND_EXPRESSION,
  PREC_EQUALITY_EXPRESSION,
  PREC_RELATIONAL_EXPRESSION,
  PREC_SHIFT_EXPRESSION,
  PREC_ADDITIVE_EXPRESSION,
  PREC_MULTIPLICATIVE_EXPRESSION,
  PREC_PM_EXPRESSION,
  NUM_PREC_VALUES = PREC_PM_EXPRESSION
};

/* A mapping from a token type to a corresponding tree node type, with a
   precedence value.  */

typedef struct cp_parser_binary_operations_map_node
{
  /* The token type.  */
  enum cpp_ttype token_type;
  /* The corresponding tree code.  */
  enum tree_code tree_type;
  /* The precedence of this operator.  */
  enum cp_parser_prec prec;
} cp_parser_binary_operations_map_node;

/* The status of a tentative parse.  */

typedef enum cp_parser_status_kind
{
  /* No errors have occurred.  */
  CP_PARSER_STATUS_KIND_NO_ERROR,
  /* An error has occurred.  */
  CP_PARSER_STATUS_KIND_ERROR,
  /* We are committed to this tentative parse, whether or not an error
     has occurred.  */
  CP_PARSER_STATUS_KIND_COMMITTED
} cp_parser_status_kind;

typedef struct cp_parser_expression_stack_entry
{
  tree lhs;
  enum tree_code tree_type;
  int prec;
} cp_parser_expression_stack_entry;

/* The stack for storing partial expressions.  We only need NUM_PREC_VALUES
   entries because precedence levels on the stack are monotonically
   increasing.  */
typedef struct cp_parser_expression_stack_entry
  cp_parser_expression_stack[NUM_PREC_VALUES];

/* Context that is saved and restored when parsing tentatively.  */
typedef struct cp_parser_context GTY (())
{
  /* If this is a tentative parsing context, the status of the
     tentative parse.  */
  enum cp_parser_status_kind status;
  /* If non-NULL, we have just seen a `x->' or `x.' expression.  Names
     that are looked up in this context must be looked up both in the
     scope given by OBJECT_TYPE (the type of `x' or `*x') and also in
     the context of the containing expression.  */
  tree object_type;

  /* The next parsing context in the stack.  */
  struct cp_parser_context *next;
} cp_parser_context;

/* Prototypes.  */

/* Constructors and destructors.  */

static cp_parser_context *cp_parser_context_new
  (cp_parser_context *);

/* Class variables.  */

static GTY((deletable)) cp_parser_context* cp_parser_context_free_list;

/* The operator-precedence table used by cp_parser_binary_expression.
   Transformed into an associative array (binops_by_token) by
   cp_parser_new.  */

static const cp_parser_binary_operations_map_node binops[] = {
  { CPP_DEREF_STAR, MEMBER_REF, PREC_PM_EXPRESSION },
  { CPP_DOT_STAR, DOTSTAR_EXPR, PREC_PM_EXPRESSION },

  { CPP_MULT, MULT_EXPR, PREC_MULTIPLICATIVE_EXPRESSION },
  { CPP_DIV, TRUNC_DIV_EXPR, PREC_MULTIPLICATIVE_EXPRESSION },
  { CPP_MOD, TRUNC_MOD_EXPR, PREC_MULTIPLICATIVE_EXPRESSION },

  { CPP_PLUS, PLUS_EXPR, PREC_ADDITIVE_EXPRESSION },
  { CPP_MINUS, MINUS_EXPR, PREC_ADDITIVE_EXPRESSION },

  { CPP_LSHIFT, LSHIFT_EXPR, PREC_SHIFT_EXPRESSION },
  { CPP_RSHIFT, RSHIFT_EXPR, PREC_SHIFT_EXPRESSION },

  { CPP_LESS, LT_EXPR, PREC_RELATIONAL_EXPRESSION },
  { CPP_GREATER, GT_EXPR, PREC_RELATIONAL_EXPRESSION },
  { CPP_LESS_EQ, LE_EXPR, PREC_RELATIONAL_EXPRESSION },
  { CPP_GREATER_EQ, GE_EXPR, PREC_RELATIONAL_EXPRESSION },
  { CPP_MIN, MIN_EXPR, PREC_RELATIONAL_EXPRESSION },
  { CPP_MAX, MAX_EXPR, PREC_RELATIONAL_EXPRESSION },

  { CPP_EQ_EQ, EQ_EXPR, PREC_EQUALITY_EXPRESSION },
  { CPP_NOT_EQ, NE_EXPR, PREC_EQUALITY_EXPRESSION },

  { CPP_AND, BIT_AND_EXPR, PREC_AND_EXPRESSION },

  { CPP_XOR, BIT_XOR_EXPR, PREC_EXCLUSIVE_OR_EXPRESSION },

  { CPP_OR, BIT_IOR_EXPR, PREC_INCLUSIVE_OR_EXPRESSION },

  { CPP_AND_AND, TRUTH_ANDIF_EXPR, PREC_LOGICAL_AND_EXPRESSION },

  { CPP_OR_OR, TRUTH_ORIF_EXPR, PREC_LOGICAL_OR_EXPRESSION }
};

/* The same as binops, but initialized by cp_parser_new so that
   binops_by_token[N].token_type == N.  Used in cp_parser_binary_expression
   for speed.  */
static cp_parser_binary_operations_map_node binops_by_token[N_CP_TTYPES];

/* Constructors and destructors.  */

/* Construct a new context.  The context below this one on the stack
   is given by NEXT.  */

static cp_parser_context *
cp_parser_context_new (cp_parser_context* next)
{
  cp_parser_context *context;

  /* Allocate the storage.  */
  if (cp_parser_context_free_list != NULL)
    {
      /* Pull the first entry from the free list.  */
      context = cp_parser_context_free_list;
      cp_parser_context_free_list = context->next;
      memset (context, 0, sizeof (*context));
    }
  else
    context = GGC_CNEW (cp_parser_context);

  /* No errors have occurred yet in this context.  */
  context->status = CP_PARSER_STATUS_KIND_NO_ERROR;
  /* If this is not the bottomost context, copy information that we
     need from the previous context.  */
  if (next)
    {
      /* If, in the NEXT context, we are parsing an `x->' or `x.'
         expression, then we are parsing one in this context, too.  */
      context->object_type = next->object_type;
      /* Thread the stack.  */
      context->next = next;
    }

  return context;
}

/* The cp_parser structure represents the C++ parser.  */

typedef struct cp_parser GTY(())
{
  /* The lexer from which we are obtaining tokens.  */
  cp_lexer *lexer;

  /* The scope in which names should be looked up.  If NULL_TREE, then
     we look up names in the scope that is currently open in the
     source program.  If non-NULL, this is either a TYPE or
     NAMESPACE_DECL for the scope in which we should look.  It can
     also be ERROR_MARK, when we've parsed a bogus scope.

     This value is not cleared automatically after a name is looked
     up, so we must be careful to clear it before starting a new look
     up sequence.  (If it is not cleared, then `X::Y' followed by `Z'
     will look up `Z' in the scope of `X', rather than the current
     scope.)  Unfortunately, it is difficult to tell when name lookup
     is complete, because we sometimes peek at a token, look it up,
     and then decide not to consume it.   */
  tree scope;

  /* OBJECT_SCOPE and QUALIFYING_SCOPE give the scopes in which the
     last lookup took place.  OBJECT_SCOPE is used if an expression
     like "x->y" or "x.y" was used; it gives the type of "*x" or "x",
     respectively.  QUALIFYING_SCOPE is used for an expression of the
     form "X::Y"; it refers to X.  */
  tree object_scope;
  tree qualifying_scope;

  /* A stack of parsing contexts.  All but the bottom entry on the
     stack will be tentative contexts.

     We parse tentatively in order to determine which construct is in
     use in some situations.  For example, in order to determine
     whether a statement is an expression-statement or a
     declaration-statement we parse it tentatively as a
     declaration-statement.  If that fails, we then reparse the same
     token stream as an expression-statement.  */
  cp_parser_context *context;

  /* True if we are parsing GNU C++.  If this flag is not set, then
     GNU extensions are not recognized.  */
  bool allow_gnu_extensions_p;

  /* TRUE if the `>' token should be interpreted as the greater-than
     operator.  FALSE if it is the end of a template-id or
     template-parameter-list.  */
  bool greater_than_is_operator_p;

  /* TRUE if default arguments are allowed within a parameter list
     that starts at this point. FALSE if only a gnu extension makes
     them permissible.  */
  bool default_arg_ok_p;

  /* TRUE if we are parsing an integral constant-expression.  See
     [expr.const] for a precise definition.  */
  bool integral_constant_expression_p;

  /* TRUE if we are parsing an integral constant-expression -- but a
     non-constant expression should be permitted as well.  This flag
     is used when parsing an array bound so that GNU variable-length
     arrays are tolerated.  */
  bool allow_non_integral_constant_expression_p;

  /* TRUE if ALLOW_NON_CONSTANT_EXPRESSION_P is TRUE and something has
     been seen that makes the expression non-constant.  */
  bool non_integral_constant_expression_p;

  /* TRUE if local variable names and `this' are forbidden in the
     current context.  */
  bool local_variables_forbidden_p;

  /* TRUE if the declaration we are parsing is part of a
     linkage-specification of the form `extern string-literal
     declaration'.  */
  bool in_unbraced_linkage_specification_p;

  /* TRUE if we are presently parsing a declarator, after the
     direct-declarator.  */
  bool in_declarator_p;

  /* TRUE if we are presently parsing a template-argument-list.  */
  bool in_template_argument_list_p;

  /* TRUE if we are presently parsing the body of an
     iteration-statement.  */
  bool in_iteration_statement_p;

  /* TRUE if we are presently parsing the body of a switch
     statement.  */
  bool in_switch_statement_p;

  /* TRUE if we are parsing a type-id in an expression context.  In
     such a situation, both "type (expr)" and "type (type)" are valid
     alternatives.  */
  bool in_type_id_in_expr_p;

  /* TRUE if we are currently in a header file where declarations are
     implicitly extern "C".  */
  bool implicit_extern_c;

  /* TRUE if strings in expressions should be translated to the execution
     character set.  */
  bool translate_strings_p;

  /* If non-NULL, then we are parsing a construct where new type
     definitions are not permitted.  The string stored here will be
     issued as an error message if a type is defined.  */
  const char *type_definition_forbidden_message;

  /* A list of lists. The outer list is a stack, used for member
     functions of local classes. At each level there are two sub-list,
     one on TREE_VALUE and one on TREE_PURPOSE. Each of those
     sub-lists has a FUNCTION_DECL or TEMPLATE_DECL on their
     TREE_VALUE's. The functions are chained in reverse declaration
     order.

     The TREE_PURPOSE sublist contains those functions with default
     arguments that need post processing, and the TREE_VALUE sublist
     contains those functions with definitions that need post
     processing.

     These lists can only be processed once the outermost class being
     defined is complete.  */
  tree unparsed_functions_queues;

  /* The number of classes whose definitions are currently in
     progress.  */
  unsigned num_classes_being_defined;

  /* The number of template parameter lists that apply directly to the
     current declaration.  */
  unsigned num_template_parameter_lists;
} cp_parser;

/* The type of a function that parses some kind of expression.  */
typedef tree (*cp_parser_expression_fn) (cp_parser *);

/* Prototypes.  */

/* Constructors and destructors.  */

static cp_parser *cp_parser_new
  (void);

/* Routines to parse various constructs.

   Those that return `tree' will return the error_mark_node (rather
   than NULL_TREE) if a parse error occurs, unless otherwise noted.
   Sometimes, they will return an ordinary node if error-recovery was
   attempted, even though a parse error occurred.  So, to check
   whether or not a parse error occurred, you should always use
   cp_parser_error_occurred.  If the construct is optional (indicated
   either by an `_opt' in the name of the function that does the
   parsing or via a FLAGS parameter), then NULL_TREE is returned if
   the construct is not present.  */

/* Lexical conventions [gram.lex]  */

static tree cp_parser_identifier
  (cp_parser *);
static tree cp_parser_string_literal
  (cp_parser *, bool, bool);

/* Basic concepts [gram.basic]  */

static bool cp_parser_translation_unit
  (cp_parser *);

/* Expressions [gram.expr]  */

static tree cp_parser_primary_expression
  (cp_parser *, bool, bool, bool, cp_id_kind *);
static tree cp_parser_id_expression
  (cp_parser *, bool, bool, bool *, bool);
static tree cp_parser_unqualified_id
  (cp_parser *, bool, bool, bool);
static tree cp_parser_nested_name_specifier_opt
  (cp_parser *, bool, bool, bool, bool);
static tree cp_parser_nested_name_specifier
  (cp_parser *, bool, bool, bool, bool);
static tree cp_parser_class_or_namespace_name
  (cp_parser *, bool, bool, bool, bool, bool);
static tree cp_parser_postfix_expression
  (cp_parser *, bool, bool);
static tree cp_parser_postfix_open_square_expression
  (cp_parser *, tree, bool);
static tree cp_parser_postfix_dot_deref_expression
  (cp_parser *, enum cpp_ttype, tree, bool, cp_id_kind *);
static tree cp_parser_parenthesized_expression_list
  (cp_parser *, bool, bool, bool *);
static void cp_parser_pseudo_destructor_name
  (cp_parser *, tree *, tree *);
static tree cp_parser_unary_expression
  (cp_parser *, bool, bool);
static enum tree_code cp_parser_unary_operator
  (cp_token *);
static tree cp_parser_new_expression
  (cp_parser *);
static tree cp_parser_new_placement
  (cp_parser *);
static tree cp_parser_new_type_id
  (cp_parser *, tree *);
static cp_declarator *cp_parser_new_declarator_opt
  (cp_parser *);
static cp_declarator *cp_parser_direct_new_declarator
  (cp_parser *);
static tree cp_parser_new_initializer
  (cp_parser *);
static tree cp_parser_delete_expression
  (cp_parser *);
static tree cp_parser_cast_expression
  (cp_parser *, bool, bool);
static tree cp_parser_binary_expression
  (cp_parser *, bool);
static tree cp_parser_question_colon_clause
  (cp_parser *, tree);
static tree cp_parser_assignment_expression
  (cp_parser *, bool);
static enum tree_code cp_parser_assignment_operator_opt
  (cp_parser *);
static tree cp_parser_expression
  (cp_parser *, bool);
static tree cp_parser_constant_expression
  (cp_parser *, bool, bool *);
static tree cp_parser_builtin_offsetof
  (cp_parser *);

/* Statements [gram.stmt.stmt]  */

static void cp_parser_statement
  (cp_parser *, tree);
static tree cp_parser_labeled_statement
  (cp_parser *, tree);
static tree cp_parser_expression_statement
  (cp_parser *, tree);
static tree cp_parser_compound_statement
  (cp_parser *, tree, bool);
static void cp_parser_statement_seq_opt
  (cp_parser *, tree);
static tree cp_parser_selection_statement
  (cp_parser *);
static tree cp_parser_condition
  (cp_parser *);
static tree cp_parser_iteration_statement
  (cp_parser *);
static void cp_parser_for_init_statement
  (cp_parser *);
static tree cp_parser_jump_statement
  (cp_parser *);
static void cp_parser_declaration_statement
  (cp_parser *);

static tree cp_parser_implicitly_scoped_statement
  (cp_parser *);
static void cp_parser_already_scoped_statement
  (cp_parser *);

/* Declarations [gram.dcl.dcl] */

static void cp_parser_declaration_seq_opt
  (cp_parser *);
static void cp_parser_declaration
  (cp_parser *);
static void cp_parser_block_declaration
  (cp_parser *, bool);
static void cp_parser_simple_declaration
  (cp_parser *, bool);
static void cp_parser_decl_specifier_seq
  (cp_parser *, cp_parser_flags, cp_decl_specifier_seq *, int *);
static tree cp_parser_storage_class_specifier_opt
  (cp_parser *);
static tree cp_parser_function_specifier_opt
  (cp_parser *, cp_decl_specifier_seq *);
static tree cp_parser_type_specifier
  (cp_parser *, cp_parser_flags, cp_decl_specifier_seq *, bool,
   int *, bool *);
static tree cp_parser_simple_type_specifier
  (cp_parser *, cp_decl_specifier_seq *, cp_parser_flags);
static tree cp_parser_type_name
  (cp_parser *);
static tree cp_parser_elaborated_type_specifier
  (cp_parser *, bool, bool);
static tree cp_parser_enum_specifier
  (cp_parser *);
static void cp_parser_enumerator_list
  (cp_parser *, tree);
static void cp_parser_enumerator_definition
  (cp_parser *, tree);
static tree cp_parser_namespace_name
  (cp_parser *);
static void cp_parser_namespace_definition
  (cp_parser *);
static void cp_parser_namespace_body
  (cp_parser *);
static tree cp_parser_qualified_namespace_specifier
  (cp_parser *);
static void cp_parser_namespace_alias_definition
  (cp_parser *);
static void cp_parser_using_declaration
  (cp_parser *);
static void cp_parser_using_directive
  (cp_parser *);
static void cp_parser_asm_definition
  (cp_parser *);
static void cp_parser_linkage_specification
  (cp_parser *);

/* Declarators [gram.dcl.decl] */

static tree cp_parser_init_declarator
  (cp_parser *, cp_decl_specifier_seq *, bool, bool, int, bool *);
static cp_declarator *cp_parser_declarator
  (cp_parser *, cp_parser_declarator_kind, int *, bool *, bool);
static cp_declarator *cp_parser_direct_declarator
  (cp_parser *, cp_parser_declarator_kind, int *, bool);
static enum tree_code cp_parser_ptr_operator
  (cp_parser *, tree *, cp_cv_quals *);
static cp_cv_quals cp_parser_cv_qualifier_seq_opt
  (cp_parser *);
static tree cp_parser_declarator_id
  (cp_parser *);
static tree cp_parser_type_id
  (cp_parser *);
static void cp_parser_type_specifier_seq
  (cp_parser *, bool, cp_decl_specifier_seq *);
static cp_parameter_declarator *cp_parser_parameter_declaration_clause
  (cp_parser *);
static cp_parameter_declarator *cp_parser_parameter_declaration_list
  (cp_parser *, bool *);
static cp_parameter_declarator *cp_parser_parameter_declaration
  (cp_parser *, bool, bool *);
static void cp_parser_function_body
  (cp_parser *);
static tree cp_parser_initializer
  (cp_parser *, bool *, bool *);
static tree cp_parser_initializer_clause
  (cp_parser *, bool *);
static VEC(constructor_elt,gc) *cp_parser_initializer_list
  (cp_parser *, bool *);

static bool cp_parser_ctor_initializer_opt_and_function_body
  (cp_parser *);

/* Classes [gram.class] */

static tree cp_parser_class_name
  (cp_parser *, bool, bool, enum tag_types, bool, bool, bool);
static tree cp_parser_class_specifier
  (cp_parser *);
static tree cp_parser_class_head
  (cp_parser *, bool *, tree *);
static enum tag_types cp_parser_class_key
  (cp_parser *);
static void cp_parser_member_specification_opt
  (cp_parser *);
static void cp_parser_member_declaration
  (cp_parser *);
static tree cp_parser_pure_specifier
  (cp_parser *);
static tree cp_parser_constant_initializer
  (cp_parser *);

/* Derived classes [gram.class.derived] */

static tree cp_parser_base_clause
  (cp_parser *);
static tree cp_parser_base_specifier
  (cp_parser *);

/* Special member functions [gram.special] */

static tree cp_parser_conversion_function_id
  (cp_parser *);
static tree cp_parser_conversion_type_id
  (cp_parser *);
static cp_declarator *cp_parser_conversion_declarator_opt
  (cp_parser *);
static bool cp_parser_ctor_initializer_opt
  (cp_parser *);
static void cp_parser_mem_initializer_list
  (cp_parser *);
static tree cp_parser_mem_initializer
  (cp_parser *);
static tree cp_parser_mem_initializer_id
  (cp_parser *);

/* Overloading [gram.over] */

static tree cp_parser_operator_function_id
  (cp_parser *);
static tree cp_parser_operator
  (cp_parser *);

/* Templates [gram.temp] */

static void cp_parser_template_declaration
  (cp_parser *, bool);
static tree cp_parser_template_parameter_list
  (cp_parser *);
static tree cp_parser_template_parameter
  (cp_parser *, bool *);
static tree cp_parser_type_parameter
  (cp_parser *);
static tree cp_parser_template_id
  (cp_parser *, bool, bool, bool);
static tree cp_parser_template_name
  (cp_parser *, bool, bool, bool, bool *);
static tree cp_parser_template_argument_list
  (cp_parser *);
static tree cp_parser_template_argument
  (cp_parser *);
static void cp_parser_explicit_instantiation
  (cp_parser *);
static void cp_parser_explicit_specialization
  (cp_parser *);

/* Exception handling [gram.exception] */

static tree cp_parser_try_block
  (cp_parser *);
static bool cp_parser_function_try_block
  (cp_parser *);
static void cp_parser_handler_seq
  (cp_parser *);
static void cp_parser_handler
  (cp_parser *);
static tree cp_parser_exception_declaration
  (cp_parser *);
static tree cp_parser_throw_expression
  (cp_parser *);
static tree cp_parser_exception_specification_opt
  (cp_parser *);
static tree cp_parser_type_id_list
  (cp_parser *);

/* GNU Extensions */

static tree cp_parser_asm_specification_opt
  (cp_parser *);
static tree cp_parser_asm_operand_list
  (cp_parser *);
static tree cp_parser_asm_clobber_list
  (cp_parser *);
static tree cp_parser_attributes_opt
  (cp_parser *);
static tree cp_parser_attribute_list
  (cp_parser *);
static bool cp_parser_extension_opt
  (cp_parser *, int *);
static void cp_parser_label_declaration
  (cp_parser *);

/* Objective-C++ Productions */

static tree cp_parser_objc_message_receiver
  (cp_parser *);
static tree cp_parser_objc_message_args
  (cp_parser *);
static tree cp_parser_objc_message_expression
  (cp_parser *);
static tree cp_parser_objc_encode_expression
  (cp_parser *);
static tree cp_parser_objc_defs_expression
  (cp_parser *);
static tree cp_parser_objc_protocol_expression
  (cp_parser *);
static tree cp_parser_objc_selector_expression
  (cp_parser *);
static tree cp_parser_objc_expression
  (cp_parser *);
static bool cp_parser_objc_selector_p
  (enum cpp_ttype);
static tree cp_parser_objc_selector
  (cp_parser *);
static tree cp_parser_objc_protocol_refs_opt
  (cp_parser *);
static void cp_parser_objc_declaration
  (cp_parser *);
static tree cp_parser_objc_statement
  (cp_parser *);

/* Utility Routines */

static tree cp_parser_lookup_name
  (cp_parser *, tree, enum tag_types, bool, bool, bool, bool *);
static tree cp_parser_lookup_name_simple
  (cp_parser *, tree);
static tree cp_parser_maybe_treat_template_as_class
  (tree, bool);
static bool cp_parser_check_declarator_template_parameters
  (cp_parser *, cp_declarator *);
static bool cp_parser_check_template_parameters
  (cp_parser *, unsigned);
static tree cp_parser_simple_cast_expression
  (cp_parser *);
static tree cp_parser_global_scope_opt
  (cp_parser *, bool);
static bool cp_parser_constructor_declarator_p
  (cp_parser *, bool);
static tree cp_parser_function_definition_from_specifiers_and_declarator
  (cp_parser *, cp_decl_specifier_seq *, tree, const cp_declarator *);
static tree cp_parser_function_definition_after_declarator
  (cp_parser *, bool);
static void cp_parser_template_declaration_after_export
  (cp_parser *, bool);
static tree cp_parser_single_declaration
  (cp_parser *, bool, bool *);
static tree cp_parser_functional_cast
  (cp_parser *, tree);
static tree cp_parser_save_member_function_body
  (cp_parser *, cp_decl_specifier_seq *, cp_declarator *, tree);
static tree cp_parser_enclosed_template_argument_list
  (cp_parser *);
static void cp_parser_save_default_args
  (cp_parser *, tree);
static void cp_parser_late_parsing_for_member
  (cp_parser *, tree);
static void cp_parser_late_parsing_default_args
  (cp_parser *, tree);
static tree cp_parser_sizeof_operand
  (cp_parser *, enum rid);
static bool cp_parser_declares_only_class_p
  (cp_parser *);
static void cp_parser_set_storage_class
  (cp_decl_specifier_seq *, cp_storage_class);
static void cp_parser_set_decl_spec_type
  (cp_decl_specifier_seq *, tree, bool);
static bool cp_parser_friend_p
  (const cp_decl_specifier_seq *);
static cp_token *cp_parser_require
  (cp_parser *, enum cpp_ttype, const char *);
static cp_token *cp_parser_require_keyword
  (cp_parser *, enum rid, const char *);
static bool cp_parser_token_starts_function_definition_p
  (cp_token *);
static bool cp_parser_next_token_starts_class_definition_p
  (cp_parser *);
static bool cp_parser_next_token_ends_template_argument_p
  (cp_parser *);
static bool cp_parser_nth_token_starts_template_argument_list_p
  (cp_parser *, size_t);
static enum tag_types cp_parser_token_is_class_key
  (cp_token *);
static void cp_parser_check_class_key
  (enum tag_types, tree type);
static void cp_parser_check_access_in_redeclaration
  (tree type);
static bool cp_parser_optional_template_keyword
  (cp_parser *);
static void cp_parser_pre_parsed_nested_name_specifier
  (cp_parser *);
static void cp_parser_cache_group
  (cp_parser *, enum cpp_ttype, unsigned);
static void cp_parser_parse_tentatively
  (cp_parser *);
static void cp_parser_commit_to_tentative_parse
  (cp_parser *);
static void cp_parser_abort_tentative_parse
  (cp_parser *);
static bool cp_parser_parse_definitely
  (cp_parser *);
static inline bool cp_parser_parsing_tentatively
  (cp_parser *);
static bool cp_parser_uncommitted_to_tentative_parse_p
  (cp_parser *);
static void cp_parser_error
  (cp_parser *, const char *);
static void cp_parser_name_lookup_error
  (cp_parser *, tree, tree, const char *);
static bool cp_parser_simulate_error
  (cp_parser *);
static void cp_parser_check_type_definition
  (cp_parser *);
static void cp_parser_check_for_definition_in_return_type
  (cp_declarator *, tree);
static void cp_parser_check_for_invalid_template_id
  (cp_parser *, tree);
static bool cp_parser_non_integral_constant_expression
  (cp_parser *, const char *);
static void cp_parser_diagnose_invalid_type_name
  (cp_parser *, tree, tree);
static bool cp_parser_parse_and_diagnose_invalid_type_name
  (cp_parser *);
static int cp_parser_skip_to_closing_parenthesis
  (cp_parser *, bool, bool, bool);
static void cp_parser_skip_to_end_of_statement
  (cp_parser *);
static void cp_parser_consume_semicolon_at_end_of_statement
  (cp_parser *);
static void cp_parser_skip_to_end_of_block_or_statement
  (cp_parser *);
static void cp_parser_skip_to_closing_brace
  (cp_parser *);
static void cp_parser_skip_until_found
  (cp_parser *, enum cpp_ttype, const char *);
static bool cp_parser_error_occurred
  (cp_parser *);
static bool cp_parser_allow_gnu_extensions_p
  (cp_parser *);
static bool cp_parser_is_string_literal
  (cp_token *);
static bool cp_parser_is_keyword
  (cp_token *, enum rid);
static tree cp_parser_make_typename_type
  (cp_parser *, tree, tree);

/* Returns nonzero if we are parsing tentatively.  */

static inline bool
cp_parser_parsing_tentatively (cp_parser* parser)
{
  return parser->context->next != NULL;
}

/* Returns nonzero if TOKEN is a string literal.  */

static bool
cp_parser_is_string_literal (cp_token* token)
{
  return (token->type == CPP_STRING || token->type == CPP_WSTRING);
}

/* Returns nonzero if TOKEN is the indicated KEYWORD.  */

static bool
cp_parser_is_keyword (cp_token* token, enum rid keyword)
{
  return token->keyword == keyword;
}

/* A minimum or maximum operator has been seen.  As these are
   deprecated, issue a warning.  */

static inline void
cp_parser_warn_min_max (void)
{
  if (warn_deprecated && !in_system_header)
    warning (0, "minimum/maximum operators are deprecated");
}

/* If not parsing tentatively, issue a diagnostic of the form
      FILE:LINE: MESSAGE before TOKEN
   where TOKEN is the next token in the input stream.  MESSAGE
   (specified by the caller) is usually of the form "expected
   OTHER-TOKEN".  */

static void
cp_parser_error (cp_parser* parser, const char* message)
{
  if (!cp_parser_simulate_error (parser))
    {
      cp_token *token = cp_lexer_peek_token (parser->lexer);
      /* This diagnostic makes more sense if it is tagged to the line
         of the token we just peeked at.  */
      cp_lexer_set_source_position_from_token (token);
      if (token->type == CPP_PRAGMA)
        {
          error ("%<#pragma%> is not allowed here");
          cp_lexer_purge_token (parser->lexer);
          return;
        }
      c_parse_error (message,
                     /* Because c_parser_error does not understand
                        CPP_KEYWORD, keywords are treated like
                        identifiers.  */
                     (token->type == CPP_KEYWORD ? CPP_NAME : token->type),
                     token->value);
    }
}

/* Issue an error about name-lookup failing.  NAME is the
   IDENTIFIER_NODE DECL is the result of
   the lookup (as returned from cp_parser_lookup_name).  DESIRED is
   the thing that we hoped to find.  */

static void
cp_parser_name_lookup_error (cp_parser* parser,
                             tree name,
                             tree decl,
                             const char* desired)
{
  /* If name lookup completely failed, tell the user that NAME was not
     declared.  */
  if (decl == error_mark_node)
    {
      if (parser->scope && parser->scope != global_namespace)
        error ("%<%D::%D%> has not been declared",
               parser->scope, name);
      else if (parser->scope == global_namespace)
        error ("%<::%D%> has not been declared", name);
      else if (parser->object_scope
               && !CLASS_TYPE_P (parser->object_scope))
        error ("request for member %qD in non-class type %qT",
               name, parser->object_scope);
      else if (parser->object_scope)
        error ("%<%T::%D%> has not been declared",
               parser->object_scope, name);
      else
        error ("%qD has not been declared", name);
    }
  else if (parser->scope && parser->scope != global_namespace)
    error ("%<%D::%D%> %s", parser->scope, name, desired);
  else if (parser->scope == global_namespace)
    error ("%<::%D%> %s", name, desired);
  else
    error ("%qD %s", name, desired);
}

/* If we are parsing tentatively, remember that an error has occurred
   during this tentative parse.  Returns true if the error was
   simulated; false if a message should be issued by the caller.  */

static bool
cp_parser_simulate_error (cp_parser* parser)
{
  if (cp_parser_uncommitted_to_tentative_parse_p (parser))
    {
      parser->context->status = CP_PARSER_STATUS_KIND_ERROR;
      return true;
    }
  return false;
}

/* This function is called when a type is defined.  If type
   definitions are forbidden at this point, an error message is
   issued.  */

static void
cp_parser_check_type_definition (cp_parser* parser)
{
  /* If types are forbidden here, issue a message.  */
  if (parser->type_definition_forbidden_message)
    /* Use `%s' to print the string in case there are any escape
       characters in the message.  */
    error ("%s", parser->type_definition_forbidden_message);
}

/* This function is called when the DECLARATOR is processed.  The TYPE
   was a type defined in the decl-specifiers.  If it is invalid to
   define a type in the decl-specifiers for DECLARATOR, an error is
   issued.  */

static void
cp_parser_check_for_definition_in_return_type (cp_declarator *declarator,
                                               tree type)
{
  /* [dcl.fct] forbids type definitions in return types.
     Unfortunately, it's not easy to know whether or not we are
     processing a return type until after the fact.  */
  while (declarator
         && (declarator->kind == cdk_pointer
             || declarator->kind == cdk_reference
             || declarator->kind == cdk_ptrmem))
    declarator = declarator->declarator;
  if (declarator
      && declarator->kind == cdk_function)
    {
      error ("new types may not be defined in a return type");
      inform ("(perhaps a semicolon is missing after the definition of %qT)",
              type);
    }
}

/* A type-specifier (TYPE) has been parsed which cannot be followed by
   "<" in any valid C++ program.  If the next token is indeed "<",
   issue a message warning the user about what appears to be an
   invalid attempt to form a template-id.  */

static void
cp_parser_check_for_invalid_template_id (cp_parser* parser,
                                         tree type)
{
  cp_token_position start = 0;

  if (cp_lexer_next_token_is (parser->lexer, CPP_LESS))
    {
      if (TYPE_P (type))
        error ("%qT is not a template", type);
      else if (TREE_CODE (type) == IDENTIFIER_NODE)
        error ("%qE is not a template", type);
      else
        error ("invalid template-id");
      /* Remember the location of the invalid "<".  */
      if (cp_parser_uncommitted_to_tentative_parse_p (parser))
        start = cp_lexer_token_position (parser->lexer, true);
      /* Consume the "<".  */
      cp_lexer_consume_token (parser->lexer);
      /* Parse the template arguments.  */
      cp_parser_enclosed_template_argument_list (parser);
      /* Permanently remove the invalid template arguments so that
         this error message is not issued again.  */
      if (start)
        cp_lexer_purge_tokens_after (parser->lexer, start);
    }
}

/* If parsing an integral constant-expression, issue an error message
   about the fact that THING appeared and return true.  Otherwise,
   return false.  In either case, set
   PARSER->NON_INTEGRAL_CONSTANT_EXPRESSION_P.  */

static bool
cp_parser_non_integral_constant_expression (cp_parser  *parser,
                                            const char *thing)
{
  parser->non_integral_constant_expression_p = true;
  if (parser->integral_constant_expression_p)
    {
      if (!parser->allow_non_integral_constant_expression_p)
        {
          error ("%s cannot appear in a constant-expression", thing);
          return true;
        }
    }
  return false;
}

/* Emit a diagnostic for an invalid type name.  SCOPE is the
   qualifying scope (or NULL, if none) for ID.  This function commits
   to the current active tentative parse, if any.  (Otherwise, the
   problematic construct might be encountered again later, resulting
   in duplicate error messages.)  */

static void
cp_parser_diagnose_invalid_type_name (cp_parser *parser, tree scope, tree id)
{
  tree decl, old_scope;
  /* Try to lookup the identifier.  */
  old_scope = parser->scope;
  parser->scope = scope;
  decl = cp_parser_lookup_name_simple (parser, id);
  parser->scope = old_scope;
  /* If the lookup found a template-name, it means that the user forgot
  to specify an argument list. Emit a useful error message.  */
  if (TREE_CODE (decl) == TEMPLATE_DECL)
    error ("invalid use of template-name %qE without an argument list",
      decl);
  else if (!parser->scope || parser->scope == error_mark_node)
    {
      /* Issue an error message.  */
      error ("%qE does not name a type", id);
      /* If we're in a template class, it's possible that the user was
         referring to a type from a base class.  For example:

           template <typename T> struct A { typedef T X; };
           template <typename T> struct B : public A<T> { X x; };

         The user should have said "typename A<T>::X".  */
      if (processing_template_decl && current_class_type
          && TYPE_BINFO (current_class_type))
        {
          tree b;

          for (b = TREE_CHAIN (TYPE_BINFO (current_class_type));
               b;
               b = TREE_CHAIN (b))
            {
              tree base_type = BINFO_TYPE (b);
              if (CLASS_TYPE_P (base_type)
                  && dependent_type_p (base_type))
                {
                  tree field;
                  /* Go from a particular instantiation of the
                     template (which will have an empty TYPE_FIELDs),
                     to the main version.  */
                  base_type = CLASSTYPE_PRIMARY_TEMPLATE_TYPE (base_type);
                  for (field = TYPE_FIELDS (base_type);
                       field;
                       field = TREE_CHAIN (field))
                    if (TREE_CODE (field) == TYPE_DECL
                        && DECL_NAME (field) == id)
                      {
                        inform ("(perhaps %<typename %T::%E%> was intended)",
                                BINFO_TYPE (b), id);
                        break;
                      }
                  if (field)
                    break;
                }
            }
        }
    }
  /* Here we diagnose qualified-ids where the scope is actually correct,
     but the identifier does not resolve to a valid type name.  */
  else
    {
      if (TREE_CODE (parser->scope) == NAMESPACE_DECL)
        error ("%qE in namespace %qE does not name a type",
               id, parser->scope);
      else if (TYPE_P (parser->scope))
        error ("%qE in class %qT does not name a type", id, parser->scope);
      else
        gcc_unreachable ();
    }
  cp_parser_commit_to_tentative_parse (parser);
}

/* Check for a common situation where a type-name should be present,
   but is not, and issue a sensible error message.  Returns true if an
   invalid type-name was detected.

   The situation handled by this function are variable declarations of the
   form `ID a', where `ID' is an id-expression and `a' is a plain identifier.
   Usually, `ID' should name a type, but if we got here it means that it
   does not. We try to emit the best possible error message depending on
   how exactly the id-expression looks like.
*/

static bool
cp_parser_parse_and_diagnose_invalid_type_name (cp_parser *parser)
{
  tree id;

  cp_parser_parse_tentatively (parser);
  id = cp_parser_id_expression (parser,
                                /*template_keyword_p=*/false,
                                /*check_dependency_p=*/true,
                                /*template_p=*/NULL,
                                /*declarator_p=*/true);
  /* After the id-expression, there should be a plain identifier,
     otherwise this is not a simple variable declaration. Also, if
     the scope is dependent, we cannot do much.  */
  if (!cp_lexer_next_token_is (parser->lexer, CPP_NAME)
      || (parser->scope && TYPE_P (parser->scope)
          && dependent_type_p (parser->scope)))
    {
      cp_parser_abort_tentative_parse (parser);
      return false;
    }
  if (!cp_parser_parse_definitely (parser)
      || TREE_CODE (id) != IDENTIFIER_NODE)
    return false;

  /* Emit a diagnostic for the invalid type.  */
  cp_parser_diagnose_invalid_type_name (parser, parser->scope, id);
  /* Skip to the end of the declaration; there's no point in
     trying to process it.  */
  cp_parser_skip_to_end_of_block_or_statement (parser);
  return true;
}

/* Consume tokens up to, and including, the next non-nested closing `)'.
   Returns 1 iff we found a closing `)'.  RECOVERING is true, if we
   are doing error recovery. Returns -1 if OR_COMMA is true and we
   found an unnested comma.  */

static int
cp_parser_skip_to_closing_parenthesis (cp_parser *parser,
                                       bool recovering,
                                       bool or_comma,
                                       bool consume_paren)
{
  unsigned paren_depth = 0;
  unsigned brace_depth = 0;
  int result;

  if (recovering && !or_comma
      && cp_parser_uncommitted_to_tentative_parse_p (parser))
    return 0;

  while (true)
    {
      cp_token *token;

      /* If we've run out of tokens, then there is no closing `)'.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_EOF))
        {
          result = 0;
          break;
        }

      token = cp_lexer_peek_token (parser->lexer);

      /* This matches the processing in skip_to_end_of_statement.  */
      if (token->type == CPP_SEMICOLON && !brace_depth)
        {
          result = 0;
          break;
        }
      if (token->type == CPP_OPEN_BRACE)
        ++brace_depth;
      if (token->type == CPP_CLOSE_BRACE)
        {
          if (!brace_depth--)
            {
              result = 0;
              break;
            }
        }
      if (recovering && or_comma && token->type == CPP_COMMA
          && !brace_depth && !paren_depth)
        {
          result = -1;
          break;
        }

      if (!brace_depth)
        {
          /* If it is an `(', we have entered another level of nesting.  */
          if (token->type == CPP_OPEN_PAREN)
            ++paren_depth;
          /* If it is a `)', then we might be done.  */
          else if (token->type == CPP_CLOSE_PAREN && !paren_depth--)
            {
              if (consume_paren)
                cp_lexer_consume_token (parser->lexer);
              {
                result = 1;
                break;
              }
            }
        }

      /* Consume the token.  */
      cp_lexer_consume_token (parser->lexer);
    }

  return result;
}

/* Consume tokens until we reach the end of the current statement.
   Normally, that will be just before consuming a `;'.  However, if a
   non-nested `}' comes first, then we stop before consuming that.  */

static void
cp_parser_skip_to_end_of_statement (cp_parser* parser)
{
  unsigned nesting_depth = 0;

  while (true)
    {
      cp_token *token;

      /* Peek at the next token.  */
      token = cp_lexer_peek_token (parser->lexer);
      /* If we've run out of tokens, stop.  */
      if (token->type == CPP_EOF)
        break;
      /* If the next token is a `;', we have reached the end of the
         statement.  */
      if (token->type == CPP_SEMICOLON && !nesting_depth)
        break;
      /* If the next token is a non-nested `}', then we have reached
         the end of the current block.  */
      if (token->type == CPP_CLOSE_BRACE)
        {
          /* If this is a non-nested `}', stop before consuming it.
             That way, when confronted with something like:

               { 3 + }

             we stop before consuming the closing `}', even though we
             have not yet reached a `;'.  */
          if (nesting_depth == 0)
            break;
          /* If it is the closing `}' for a block that we have
             scanned, stop -- but only after consuming the token.
             That way given:

                void f g () { ... }
                typedef int I;

             we will stop after the body of the erroneously declared
             function, but before consuming the following `typedef'
             declaration.  */
          if (--nesting_depth == 0)
            {
              cp_lexer_consume_token (parser->lexer);
              break;
            }
        }
      /* If it the next token is a `{', then we are entering a new
         block.  Consume the entire block.  */
      else if (token->type == CPP_OPEN_BRACE)
        ++nesting_depth;
      /* Consume the token.  */
      cp_lexer_consume_token (parser->lexer);
    }
}

/* This function is called at the end of a statement or declaration.
   If the next token is a semicolon, it is consumed; otherwise, error
   recovery is attempted.  */

static void
cp_parser_consume_semicolon_at_end_of_statement (cp_parser *parser)
{
  /* Look for the trailing `;'.  */
  if (!cp_parser_require (parser, CPP_SEMICOLON, "`;'"))
    {
      /* If there is additional (erroneous) input, skip to the end of
         the statement.  */
      cp_parser_skip_to_end_of_statement (parser);
      /* If the next token is now a `;', consume it.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
        cp_lexer_consume_token (parser->lexer);
    }
}

/* Skip tokens until we have consumed an entire block, or until we
   have consumed a non-nested `;'.  */

static void
cp_parser_skip_to_end_of_block_or_statement (cp_parser* parser)
{
  int nesting_depth = 0;

  while (nesting_depth >= 0)
    {
      cp_token *token = cp_lexer_peek_token (parser->lexer);

      if (token->type == CPP_EOF)
        break;

      switch (token->type)
        {
        case CPP_EOF:
          /* If we've run out of tokens, stop.  */
          nesting_depth = -1;
          continue;

        case CPP_SEMICOLON:
          /* Stop if this is an unnested ';'. */
          if (!nesting_depth)
            nesting_depth = -1;
          break;

        case CPP_CLOSE_BRACE:
          /* Stop if this is an unnested '}', or closes the outermost
             nesting level.  */
          nesting_depth--;
          if (!nesting_depth)
            nesting_depth = -1;
          break;

        case CPP_OPEN_BRACE:
          /* Nest. */
          nesting_depth++;
          break;

        default:
          break;
        }

      /* Consume the token.  */
      cp_lexer_consume_token (parser->lexer);

    }
}

/* Skip tokens until a non-nested closing curly brace is the next
   token.  */

static void
cp_parser_skip_to_closing_brace (cp_parser *parser)
{
  unsigned nesting_depth = 0;

  while (true)
    {
      cp_token *token;

      /* Peek at the next token.  */
      token = cp_lexer_peek_token (parser->lexer);
      /* If we've run out of tokens, stop.  */
      if (token->type == CPP_EOF)
        break;
      /* If the next token is a non-nested `}', then we have reached
         the end of the current block.  */
      if (token->type == CPP_CLOSE_BRACE && nesting_depth-- == 0)
        break;
      /* If it the next token is a `{', then we are entering a new
         block.  Consume the entire block.  */
      else if (token->type == CPP_OPEN_BRACE)
        ++nesting_depth;
      /* Consume the token.  */
      cp_lexer_consume_token (parser->lexer);
    }
}

/* This is a simple wrapper around make_typename_type. When the id is
   an unresolved identifier node, we can provide a superior diagnostic
   using cp_parser_diagnose_invalid_type_name.  */

static tree
cp_parser_make_typename_type (cp_parser *parser, tree scope, tree id)
{
  tree result;
  if (TREE_CODE (id) == IDENTIFIER_NODE)
    {
      result = make_typename_type (scope, id, typename_type,
                                   /*complain=*/0);
      if (result == error_mark_node)
        cp_parser_diagnose_invalid_type_name (parser, scope, id);
      return result;
    }
  return make_typename_type (scope, id, typename_type, tf_error);
}


/* Create a new C++ parser.  */

static cp_parser *
cp_parser_new (void)
{
  cp_parser *parser;
  cp_lexer *lexer;
  unsigned i;

  /* cp_lexer_new_main is called before calling ggc_alloc because
     cp_lexer_new_main might load a PCH file.  */
  lexer = cp_lexer_new_main ();

  /* Initialize the binops_by_token so that we can get the tree
     directly from the token.  */
  for (i = 0; i < sizeof (binops) / sizeof (binops[0]); i++)
    binops_by_token[binops[i].token_type] = binops[i];

  parser = GGC_CNEW (cp_parser);
  parser->lexer = lexer;
  parser->context = cp_parser_context_new (NULL);

  /* For now, we always accept GNU extensions.  */
  parser->allow_gnu_extensions_p = 1;

  /* The `>' token is a greater-than operator, not the end of a
     template-id.  */
  parser->greater_than_is_operator_p = true;

  parser->default_arg_ok_p = true;

  /* We are not parsing a constant-expression.  */
  parser->integral_constant_expression_p = false;
  parser->allow_non_integral_constant_expression_p = false;
  parser->non_integral_constant_expression_p = false;

  /* Local variable names are not forbidden.  */
  parser->local_variables_forbidden_p = false;

  /* We are not processing an `extern "C"' declaration.  */
  parser->in_unbraced_linkage_specification_p = false;

  /* We are not processing a declarator.  */
  parser->in_declarator_p = false;

  /* We are not processing a template-argument-list.  */
  parser->in_template_argument_list_p = false;

  /* We are not in an iteration statement.  */
  parser->in_iteration_statement_p = false;

  /* We are not in a switch statement.  */
  parser->in_switch_statement_p = false;

  /* We are not parsing a type-id inside an expression.  */
  parser->in_type_id_in_expr_p = false;

  /* Declarations aren't implicitly extern "C".  */
  parser->implicit_extern_c = false;

  /* String literals should be translated to the execution character set.  */
  parser->translate_strings_p = true;

  /* The unparsed function queue is empty.  */
  parser->unparsed_functions_queues = build_tree_list (NULL_TREE, NULL_TREE);

  /* There are no classes being defined.  */
  parser->num_classes_being_defined = 0;

  /* No template parameters apply.  */
  parser->num_template_parameter_lists = 0;

  return parser;
}

/* Create a cp_lexer structure which will emit the tokens in CACHE
   and push it onto the parser's lexer stack.  This is used for delayed
   parsing of in-class method bodies and default arguments, and should
   not be confused with tentative parsing.  */
static void
cp_parser_push_lexer_for_tokens (cp_parser *parser, cp_token_cache *cache)
{
  cp_lexer *lexer = cp_lexer_new_from_tokens (cache);
  lexer->next = parser->lexer;
  parser->lexer = lexer;

  /* Move the current source position to that of the first token in the
     new lexer.  */
  cp_lexer_set_source_position_from_token (lexer->next_token);
}

/* Pop the top lexer off the parser stack.  This is never used for the
   "main" lexer, only for those pushed by cp_parser_push_lexer_for_tokens.  */
static void
cp_parser_pop_lexer (cp_parser *parser)
{
  cp_lexer *lexer = parser->lexer;
  parser->lexer = lexer->next;
  cp_lexer_destroy (lexer);

  /* Put the current source position back where it was before this
     lexer was pushed.  */
  cp_lexer_set_source_position_from_token (parser->lexer->next_token);
}

/* Lexical conventions [gram.lex]  */

/* Parse an identifier.  Returns an IDENTIFIER_NODE representing the
   identifier.  */

static tree
cp_parser_identifier (cp_parser* parser)
{
  cp_token *token;

  /* Look for the identifier.  */
  token = cp_parser_require (parser, CPP_NAME, "identifier");
  /* Return the value.  */
  return token ? token->value : error_mark_node;
}

/* Parse a sequence of adjacent string constants.  Returns a
   TREE_STRING representing the combined, nul-terminated string
   constant.  If TRANSLATE is true, translate the string to the
   execution character set.  If WIDE_OK is true, a wide string is
   invalid here.

   C++98 [lex.string] says that if a narrow string literal token is
   adjacent to a wide string literal token, the behavior is undefined.
   However, C99 6.4.5p4 says that this results in a wide string literal.
   We follow C99 here, for consistency with the C front end.

   This code is largely lifted from lex_string() in c-lex.c.

   FUTURE: ObjC++ will need to handle @-strings here.  */
static tree
cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok)
{
  tree value;
  bool wide = false;
  size_t count;
  struct obstack str_ob;
  cpp_string str, istr, *strs;
  cp_token *tok;

  tok = cp_lexer_peek_token (parser->lexer);
  if (!cp_parser_is_string_literal (tok))
    {
      cp_parser_error (parser, "expected string-literal");
      return error_mark_node;
    }

  /* Try to avoid the overhead of creating and destroying an obstack
     for the common case of just one string.  */
  if (!cp_parser_is_string_literal
      (cp_lexer_peek_nth_token (parser->lexer, 2)))
    {
      cp_lexer_consume_token (parser->lexer);

      str.text = (const unsigned char *)TREE_STRING_POINTER (tok->value);
      str.len = TREE_STRING_LENGTH (tok->value);
      count = 1;
      if (tok->type == CPP_WSTRING)
        wide = true;

      strs = &str;
    }
  else
    {
      gcc_obstack_init (&str_ob);
      count = 0;

      do
        {
          cp_lexer_consume_token (parser->lexer);
          count++;
          str.text = (unsigned char *)TREE_STRING_POINTER (tok->value);
          str.len = TREE_STRING_LENGTH (tok->value);
          if (tok->type == CPP_WSTRING)
            wide = true;

          obstack_grow (&str_ob, &str, sizeof (cpp_string));

          tok = cp_lexer_peek_token (parser->lexer);
        }
      while (cp_parser_is_string_literal (tok));

      strs = (cpp_string *) obstack_finish (&str_ob);
    }

  if (wide && !wide_ok)
    {
      cp_parser_error (parser, "a wide string is invalid in this context");
      wide = false;
    }

  if ((translate ? cpp_interpret_string : cpp_interpret_string_notranslate)
      (parse_in, strs, count, &istr, wide))
    {
      value = build_string (istr.len, (char *)istr.text);
      free ((void *)istr.text);

      TREE_TYPE (value) = wide ? wchar_array_type_node : char_array_type_node;
      value = fix_string_type (value);
    }
  else
    /* cpp_interpret_string has issued an error.  */
    value = error_mark_node;

  if (count > 1)
    obstack_free (&str_ob, 0);

  return value;
}


/* Basic concepts [gram.basic]  */

/* Parse a translation-unit.

   translation-unit:
     declaration-seq [opt]

   Returns TRUE if all went well.  */

static bool
cp_parser_translation_unit (cp_parser* parser)
{
  /* The address of the first non-permanent object on the declarator
     obstack.  */
  static void *declarator_obstack_base;

  bool success;

  /* Create the declarator obstack, if necessary.  */
  if (!cp_error_declarator)
    {
      gcc_obstack_init (&declarator_obstack);
      /* Create the error declarator.  */
      cp_error_declarator = make_declarator (cdk_error);
      /* Create the empty parameter list.  */
      no_parameters = make_parameter_declarator (NULL, NULL, NULL_TREE);
      /* Remember where the base of the declarator obstack lies.  */
      declarator_obstack_base = obstack_next_free (&declarator_obstack);
    }

  cp_parser_declaration_seq_opt (parser);
  
  /* If there are no tokens left then all went well.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_EOF))
    {
      /* Get rid of the token array; we don't need it any more.  */
      cp_lexer_destroy (parser->lexer);
      parser->lexer = NULL;
      
      /* This file might have been a context that's implicitly extern
         "C".  If so, pop the lang context.  (Only relevant for PCH.) */
      if (parser->implicit_extern_c)
        {
          pop_lang_context ();
          parser->implicit_extern_c = false;
        }
      
      /* Finish up.  */
      finish_translation_unit ();
      
      success = true;
    }
  else
    {
      cp_parser_error (parser, "expected declaration");
      success = false;
    }
  
  /* Make sure the declarator obstack was fully cleaned up.  */
  gcc_assert (obstack_next_free (&declarator_obstack)
              == declarator_obstack_base);

  /* All went well.  */
  return success;
}

/* Expressions [gram.expr] */

/* Parse a primary-expression.

   primary-expression:
     literal
     this
     ( expression )
     id-expression

   GNU Extensions:

   primary-expression:
     ( compound-statement )
     __builtin_va_arg ( assignment-expression , type-id )

   Objective-C++ Extension:

   primary-expression:
     objc-expression

   literal:
     __null

   ADDRESS_P is true iff this expression was immediately preceded by
   "&" and therefore might denote a pointer-to-member.  CAST_P is true
   iff this expression is the target of a cast.  TEMPLATE_ARG_P is
   true iff this expression is a tempalte argument.

   Returns a representation of the expression.  Upon return, *IDK
   indicates what kind of id-expression (if any) was present.  */

static tree
cp_parser_primary_expression (cp_parser *parser,
                              bool address_p,
                              bool cast_p,
                              bool template_arg_p,
                              cp_id_kind *idk)
{
  cp_token *token;

  /* Assume the primary expression is not an id-expression.  */
  *idk = CP_ID_KIND_NONE;

  /* Peek at the next token.  */
  token = cp_lexer_peek_token (parser->lexer);
  switch (token->type)
    {
      /* literal:
           integer-literal
           character-literal
           floating-literal
           string-literal
           boolean-literal  */
    case CPP_CHAR:
    case CPP_WCHAR:
    case CPP_NUMBER:
      token = cp_lexer_consume_token (parser->lexer);
      /* Floating-point literals are only allowed in an integral
         constant expression if they are cast to an integral or
         enumeration type.  */
      if (TREE_CODE (token->value) == REAL_CST
          && parser->integral_constant_expression_p
          && pedantic)
        {
          /* CAST_P will be set even in invalid code like "int(2.7 +
             ...)".   Therefore, we have to check that the next token
             is sure to end the cast.  */
          if (cast_p)
            {
              cp_token *next_token;

              next_token = cp_lexer_peek_token (parser->lexer);
              if (/* The comma at the end of an
                     enumerator-definition.  */
                  next_token->type != CPP_COMMA
                  /* The curly brace at the end of an enum-specifier.  */
                  && next_token->type != CPP_CLOSE_BRACE
                  /* The end of a statement.  */
                  && next_token->type != CPP_SEMICOLON
                  /* The end of the cast-expression.  */
                  && next_token->type != CPP_CLOSE_PAREN
                  /* The end of an array bound.  */
                  && next_token->type != CPP_CLOSE_SQUARE
                  /* The closing ">" in a template-argument-list.  */
                  && (next_token->type != CPP_GREATER
                      || parser->greater_than_is_operator_p))
                cast_p = false;
            }

          /* If we are within a cast, then the constraint that the
             cast is to an integral or enumeration type will be
             checked at that point.  If we are not within a cast, then
             this code is invalid.  */
          if (!cast_p)
            cp_parser_non_integral_constant_expression
              (parser, "floating-point literal");
        }
      return token->value;

    case CPP_STRING:
    case CPP_WSTRING:
      /* ??? Should wide strings be allowed when parser->translate_strings_p
         is false (i.e. in attributes)?  If not, we can kill the third
         argument to cp_parser_string_literal.  */
      return cp_parser_string_literal (parser,
                                       parser->translate_strings_p,
                                       true);

    case CPP_OPEN_PAREN:
      {
        tree expr;
        bool saved_greater_than_is_operator_p;

        /* Consume the `('.  */
        cp_lexer_consume_token (parser->lexer);
        /* Within a parenthesized expression, a `>' token is always
           the greater-than operator.  */
        saved_greater_than_is_operator_p
          = parser->greater_than_is_operator_p;
        parser->greater_than_is_operator_p = true;
        /* If we see `( { ' then we are looking at the beginning of
           a GNU statement-expression.  */
        if (cp_parser_allow_gnu_extensions_p (parser)
            && cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE))
          {
            /* Statement-expressions are not allowed by the standard.  */
            if (pedantic)
              pedwarn ("ISO C++ forbids braced-groups within expressions");

            /* And they're not allowed outside of a function-body; you
               cannot, for example, write:

                 int i = ({ int j = 3; j + 1; });

               at class or namespace scope.  */
            if (!at_function_scope_p ())
              error ("statement-expressions are allowed only inside functions");
            /* Start the statement-expression.  */
            expr = begin_stmt_expr ();
            /* Parse the compound-statement.  */
            cp_parser_compound_statement (parser, expr, false);
            /* Finish up.  */
            expr = finish_stmt_expr (expr, false);
          }
        else
          {
            /* Parse the parenthesized expression.  */
            expr = cp_parser_expression (parser, cast_p);
            /* Let the front end know that this expression was
               enclosed in parentheses. This matters in case, for
               example, the expression is of the form `A::B', since
               `&A::B' might be a pointer-to-member, but `&(A::B)' is
               not.  */
            finish_parenthesized_expr (expr);
          }
        /* The `>' token might be the end of a template-id or
           template-parameter-list now.  */
        parser->greater_than_is_operator_p
          = saved_greater_than_is_operator_p;
        /* Consume the `)'.  */
        if (!cp_parser_require (parser, CPP_CLOSE_PAREN, "`)'"))
          cp_parser_skip_to_end_of_statement (parser);

        return expr;
      }

    case CPP_KEYWORD:
      switch (token->keyword)
        {
          /* These two are the boolean literals.  */
        case RID_TRUE:
          cp_lexer_consume_token (parser->lexer);
          return boolean_true_node;
        case RID_FALSE:
          cp_lexer_consume_token (parser->lexer);
          return boolean_false_node;

          /* The `__null' literal.  */
        case RID_NULL:
          cp_lexer_consume_token (parser->lexer);
          return null_node;

          /* Recognize the `this' keyword.  */
        case RID_THIS:
          cp_lexer_consume_token (parser->lexer);
          if (parser->local_variables_forbidden_p)
            {
              error ("%<this%> may not be used in this context");
              return error_mark_node;
            }
          /* Pointers cannot appear in constant-expressions.  */
          if (cp_parser_non_integral_constant_expression (parser,
                                                          "`this'"))
            return error_mark_node;
          return finish_this_expr ();

          /* The `operator' keyword can be the beginning of an
             id-expression.  */
        case RID_OPERATOR:
          goto id_expression;

        case RID_FUNCTION_NAME:
        case RID_PRETTY_FUNCTION_NAME:
        case RID_C99_FUNCTION_NAME:
          /* The symbols __FUNCTION__, __PRETTY_FUNCTION__, and
             __func__ are the names of variables -- but they are
             treated specially.  Therefore, they are handled here,
             rather than relying on the generic id-expression logic
             below.  Grammatically, these names are id-expressions.

             Consume the token.  */
          token = cp_lexer_consume_token (parser->lexer);
          /* Look up the name.  */
          return finish_fname (token->value);

        case RID_VA_ARG:
          {
            tree expression;
            tree type;

            /* The `__builtin_va_arg' construct is used to handle
               `va_arg'.  Consume the `__builtin_va_arg' token.  */
            cp_lexer_consume_token (parser->lexer);
            /* Look for the opening `('.  */
            cp_parser_require (parser, CPP_OPEN_PAREN, "`('");
            /* Now, parse the assignment-expression.  */
            expression = cp_parser_assignment_expression (parser,
                                                          /*cast_p=*/false);
            /* Look for the `,'.  */
            cp_parser_require (parser, CPP_COMMA, "`,'");
            /* Parse the type-id.  */
            type = cp_parser_type_id (parser);
            /* Look for the closing `)'.  */
            cp_parser_require (parser, CPP_CLOSE_PAREN, "`)'");
            /* Using `va_arg' in a constant-expression is not
               allowed.  */
            if (cp_parser_non_integral_constant_expression (parser,
                                                            "`va_arg'"))
              return error_mark_node;
            return build_x_va_arg (expression, type);
          }

        case RID_OFFSETOF:
          return cp_parser_builtin_offsetof (parser);

          /* Objective-C++ expressions.  */
        case RID_AT_ENCODE:
        case RID_AT_PROTOCOL:
        case RID_AT_SELECTOR:
          return cp_parser_objc_expression (parser);

        default:
          cp_parser_error (parser, "expected primary-expression");
          return error_mark_node;
        }

      /* An id-expression can start with either an identifier, a
         `::' as the beginning of a qualified-id, or the "operator"
         keyword.  */
    case CPP_NAME:
    case CPP_SCOPE:
    case CPP_TEMPLATE_ID:
    case CPP_NESTED_NAME_SPECIFIER:
      {
        tree id_expression;
        tree decl;
        const char *error_msg;
        bool template_p;
        bool done;

      id_expression:
        /* Parse the id-expression.  */
        id_expression
          = cp_parser_id_expression (parser,
                                     /*template_keyword_p=*/false,
                                     /*check_dependency_p=*/true,
                                     &template_p,
                                     /*declarator_p=*/false);
        if (id_expression == error_mark_node)
          return error_mark_node;
        token = cp_lexer_peek_token (parser->lexer);
        done = (token->type != CPP_OPEN_SQUARE
                && token->type != CPP_OPEN_PAREN
                && token->type != CPP_DOT
                && token->type != CPP_DEREF
                && token->type != CPP_PLUS_PLUS
                && token->type != CPP_MINUS_MINUS);
        /* If we have a template-id, then no further lookup is
           required.  If the template-id was for a template-class, we
           will sometimes have a TYPE_DECL at this point.  */
        if (TREE_CODE (id_expression) == TEMPLATE_ID_EXPR
                 || TREE_CODE (id_expression) == TYPE_DECL)
          decl = id_expression;
        /* Look up the name.  */
        else
          {
            bool ambiguous_p;

            decl = cp_parser_lookup_name (parser, id_expression,
                                          none_type,
                                          template_p,
                                          /*is_namespace=*/false,
                                          /*check_dependency=*/true,
                                          &ambiguous_p);
            /* If the lookup was ambiguous, an error will already have
               been issued.  */
            if (ambiguous_p)
              return error_mark_node;

            /* In Objective-C++, an instance variable (ivar) may be preferred
               to whatever cp_parser_lookup_name() found.  */
            decl = objc_lookup_ivar (decl, id_expression);

            /* If name lookup gives us a SCOPE_REF, then the
               qualifying scope was dependent.  */
            if (TREE_CODE (decl) == SCOPE_REF)
              return decl;
            /* Check to see if DECL is a local variable in a context
               where that is forbidden.  */
            if (parser->local_variables_forbidden_p
                && local_variable_p (decl))
              {
                /* It might be that we only found DECL because we are
                   trying to be generous with pre-ISO scoping rules.
                   For example, consider:

                     int i;
                     void g() {
                       for (int i = 0; i < 10; ++i) {}
                       extern void f(int j = i);
                     }

                   Here, name look up will originally find the out
                   of scope `i'.  We need to issue a warning message,
                   but then use the global `i'.  */
                decl = check_for_out_of_scope_variable (decl);
                if (local_variable_p (decl))
                  {
                    error ("local variable %qD may not appear in this context",
                           decl);
                    return error_mark_node;
                  }
              }
          }

        decl = (finish_id_expression 
                (id_expression, decl, parser->scope,
                 idk,
                 parser->integral_constant_expression_p,
                 parser->allow_non_integral_constant_expression_p,
                 &parser->non_integral_constant_expression_p,
                 template_p, done, address_p,
                 template_arg_p,
                 &error_msg));
        if (error_msg)
          cp_parser_error (parser, error_msg);
        return decl;
      }

      /* Anything else is an error.  */
    default:
      /* ...unless we have an Objective-C++ message or string literal, that is.  */
      if (c_dialect_objc ()
          && (token->type == CPP_OPEN_SQUARE || token->type == CPP_OBJC_STRING))
        return cp_parser_objc_expression (parser);

      cp_parser_error (parser, "expected primary-expression");
      return error_mark_node;
    }
}

/* Parse an id-expression.

   id-expression:
     unqualified-id
     qualified-id

   qualified-id:
     :: [opt] nested-name-specifier template [opt] unqualified-id
     :: identifier
     :: operator-function-id
     :: template-id

   Return a representation of the unqualified portion of the
   identifier.  Sets PARSER->SCOPE to the qualifying scope if there is
   a `::' or nested-name-specifier.

   Often, if the id-expression was a qualified-id, the caller will
   want to make a SCOPE_REF to represent the qualified-id.  This
   function does not do this in order to avoid wastefully creating
   SCOPE_REFs when they are not required.

   If TEMPLATE_KEYWORD_P is true, then we have just seen the
   `template' keyword.

   If CHECK_DEPENDENCY_P is false, then names are looked up inside
   uninstantiated templates.

   If *TEMPLATE_P is non-NULL, it is set to true iff the
   `template' keyword is used to explicitly indicate that the entity
   named is a template.

   If DECLARATOR_P is true, the id-expression is appearing as part of
   a declarator, rather than as part of an expression.  */

static tree
cp_parser_id_expression (cp_parser *parser,
                         bool template_keyword_p,
                         bool check_dependency_p,
                         bool *template_p,
                         bool declarator_p)
{
  bool global_scope_p;
  bool nested_name_specifier_p;

  /* Assume the `template' keyword was not used.  */
  if (template_p)
    *template_p = template_keyword_p;

  /* Look for the optional `::' operator.  */
  global_scope_p
    = (cp_parser_global_scope_opt (parser, /*current_scope_valid_p=*/false)
       != NULL_TREE);
  /* Look for the optional nested-name-specifier.  */
  nested_name_specifier_p
    = (cp_parser_nested_name_specifier_opt (parser,
                                            /*typename_keyword_p=*/false,
                                            check_dependency_p,
                                            /*type_p=*/false,
                                            declarator_p)
       != NULL_TREE);
  /* If there is a nested-name-specifier, then we are looking at
     the first qualified-id production.  */
  if (nested_name_specifier_p)
    {
      tree saved_scope;
      tree saved_object_scope;
      tree saved_qualifying_scope;
      tree unqualified_id;
      bool is_template;

      /* See if the next token is the `template' keyword.  */
      if (!template_p)
        template_p = &is_template;
      *template_p = cp_parser_optional_template_keyword (parser);
      /* Name lookup we do during the processing of the
         unqualified-id might obliterate SCOPE.  */
      saved_scope = parser->scope;
      saved_object_scope = parser->object_scope;
      saved_qualifying_scope = parser->qualifying_scope;
      /* Process the final unqualified-id.  */
      unqualified_id = cp_parser_unqualified_id (parser, *template_p,
                                                 check_dependency_p,
                                                 declarator_p);
      /* Restore the SAVED_SCOPE for our caller.  */
      parser->scope = saved_scope;
      parser->object_scope = saved_object_scope;
      parser->qualifying_scope = saved_qualifying_scope;

      return unqualified_id;
    }
  /* Otherwise, if we are in global scope, then we are looking at one
     of the other qualified-id productions.  */
  else if (global_scope_p)
    {
      cp_token *token;
      tree id;

      /* Peek at the next token.  */
      token = cp_lexer_peek_token (parser->lexer);

      /* If it's an identifier, and the next token is not a "<", then
         we can avoid the template-id case.  This is an optimization
         for this common case.  */
      if (token->type == CPP_NAME
          && !cp_parser_nth_token_starts_template_argument_list_p
               (parser, 2))
        return cp_parser_identifier (parser);

      cp_parser_parse_tentatively (parser);
      /* Try a template-id.  */
      id = cp_parser_template_id (parser,
                                  /*template_keyword_p=*/false,
                                  /*check_dependency_p=*/true,
                                  declarator_p);
      /* If that worked, we're done.  */
      if (cp_parser_parse_definitely (parser))
        return id;

      /* Peek at the next token.  (Changes in the token buffer may
         have invalidated the pointer obtained above.)  */
      token = cp_lexer_peek_token (parser->lexer);

      switch (token->type)
        {
        case CPP_NAME:
          return cp_parser_identifier (parser);

        case CPP_KEYWORD:
          if (token->keyword == RID_OPERATOR)
            return cp_parser_operator_function_id (parser);
          /* Fall through.  */

        default:
          cp_parser_error (parser, "expected id-expression");
          return error_mark_node;
        }
    }
  else
    return cp_parser_unqualified_id (parser, template_keyword_p,
                                     /*check_dependency_p=*/true,
                                     declarator_p);
}

/* Parse an unqualified-id.

   unqualified-id:
     identifier
     operator-function-id
     conversion-function-id
     ~ class-name
     template-id

   If TEMPLATE_KEYWORD_P is TRUE, we have just seen the `template'
   keyword, in a construct like `A::template ...'.

   Returns a representation of unqualified-id.  For the `identifier'
   production, an IDENTIFIER_NODE is returned.  For the `~ class-name'
   production a BIT_NOT_EXPR is returned; the operand of the
   BIT_NOT_EXPR is an IDENTIFIER_NODE for the class-name.  For the
   other productions, see the documentation accompanying the
   corresponding parsing functions.  If CHECK_DEPENDENCY_P is false,
   names are looked up in uninstantiated templates.  If DECLARATOR_P
   is true, the unqualified-id is appearing as part of a declarator,
   rather than as part of an expression.  */

static tree
cp_parser_unqualified_id (cp_parser* parser,
                          bool template_keyword_p,
                          bool check_dependency_p,
                          bool declarator_p)
{
  cp_token *token;

  /* Peek at the next token.  */
  token = cp_lexer_peek_token (parser->lexer);

  switch (token->type)
    {
    case CPP_NAME:
      {
        tree id;

        /* We don't know yet whether or not this will be a
           template-id.  */
        cp_parser_parse_tentatively (parser);
        /* Try a template-id.  */
        id = cp_parser_template_id (parser, template_keyword_p,
                                    check_dependency_p,
                                    declarator_p);
        /* If it worked, we're done.  */
        if (cp_parser_parse_definitely (parser))
          return id;
        /* Otherwise, it's an ordinary identifier.  */
        return cp_parser_identifier (parser);
      }

    case CPP_TEMPLATE_ID:
      return cp_parser_template_id (parser, template_keyword_p,
                                    check_dependency_p,
                                    declarator_p);

    case CPP_COMPL:
      {
        tree type_decl;
        tree qualifying_scope;
        tree object_scope;
        tree scope;
        bool done;

        /* Consume the `~' token.  */
        cp_lexer_consume_token (parser->lexer);
        /* Parse the class-name.  The standard, as written, seems to
           say that:

             template <typename T> struct S { ~S (); };
             template <typename T> S<T>::~S() {}

           is invalid, since `~' must be followed by a class-name, but
           `S<T>' is dependent, and so not known to be a class.
           That's not right; we need to look in uninstantiated
           templates.  A further complication arises from:

             template <typename T> void f(T t) {
               t.T::~T();
             }

           Here, it is not possible to look up `T' in the scope of `T'
           itself.  We must look in both the current scope, and the
           scope of the containing complete expression.

           Yet another issue is:

             struct S {
               int S;
               ~S();
             };

             S::~S() {}

           The standard does not seem to say that the `S' in `~S'
           should refer to the type `S' and not the data member
           `S::S'.  */

        /* DR 244 says that we look up the name after the "~" in the
           same scope as we looked up the qualifying name.  That idea
           isn't fully worked out; it's more complicated than that.  */
        scope = parser->scope;
        object_scope = parser->object_scope;
        qualifying_scope = parser->qualifying_scope;

        /* If the name is of the form "X::~X" it's OK.  */
        if (scope && TYPE_P (scope)
            && cp_lexer_next_token_is (parser->lexer, CPP_NAME)
            && (cp_lexer_peek_nth_token (parser->lexer, 2)->type
                == CPP_OPEN_PAREN)
            && (cp_lexer_peek_token (parser->lexer)->value
                == TYPE_IDENTIFIER (scope)))
          {
            cp_lexer_consume_token (parser->lexer);
            return build_nt (BIT_NOT_EXPR, scope);
          }

        /* If there was an explicit qualification (S::~T), first look
           in the scope given by the qualification (i.e., S).  */
        done = false;
        type_decl = NULL_TREE;
        if (scope)
          {
            cp_parser_parse_tentatively (parser);
            type_decl = cp_parser_class_name (parser,
                                              /*typename_keyword_p=*/false,
                                              /*template_keyword_p=*/false,
                                              none_type,
                                              /*check_dependency=*/false,
                                              /*class_head_p=*/false,
                                              declarator_p);
            if (cp_parser_parse_definitely (parser))
              done = true;
          }
        /* In "N::S::~S", look in "N" as well.  */
        if (!done && scope && qualifying_scope)
          {
            cp_parser_parse_tentatively (parser);
            parser->scope = qualifying_scope;
            parser->object_scope = NULL_TREE;
            parser->qualifying_scope = NULL_TREE;
            type_decl
              = cp_parser_class_name (parser,
                                      /*typename_keyword_p=*/false,
                                      /*template_keyword_p=*/false,
                                      none_type,
                                      /*check_dependency=*/false,
                                      /*class_head_p=*/false,
                                      declarator_p);
            if (cp_parser_parse_definitely (parser))
              done = true;
          }
        /* In "p->S::~T", look in the scope given by "*p" as well.  */
        else if (!done && object_scope)
          {
            cp_parser_parse_tentatively (parser);
            parser->scope = object_scope;
            parser->object_scope = NULL_TREE;
            parser->qualifying_scope = NULL_TREE;
            type_decl
              = cp_parser_class_name (parser,
                                      /*typename_keyword_p=*/false,
                                      /*template_keyword_p=*/false,
                                      none_type,
                                      /*check_dependency=*/false,
                                      /*class_head_p=*/false,
                                      declarator_p);
            if (cp_parser_parse_definitely (parser))
              done = true;
          }
        /* Look in the surrounding context.  */
        if (!done)
          {
            parser->scope = NULL_TREE;
            parser->object_scope = NULL_TREE;
            parser->qualifying_scope = NULL_TREE;
            type_decl
              = cp_parser_class_name (parser,
                                      /*typename_keyword_p=*/false,
                                      /*template_keyword_p=*/false,
                                      none_type,
                                      /*check_dependency=*/false,
                                      /*class_head_p=*/false,
                                      declarator_p);
          }
        /* If an error occurred, assume that the name of the
           destructor is the same as the name of the qualifying
           class.  That allows us to keep parsing after running
           into ill-formed destructor names.  */
        if (type_decl == error_mark_node && scope && TYPE_P (scope))
          return build_nt (BIT_NOT_EXPR, scope);
        else if (type_decl == error_mark_node)
          return error_mark_node;

        /* [class.dtor]

           A typedef-name that names a class shall not be used as the
           identifier in the declarator for a destructor declaration.  */
        if (declarator_p
            && !DECL_IMPLICIT_TYPEDEF_P (type_decl)
            && !DECL_SELF_REFERENCE_P (type_decl)
            && !cp_parser_uncommitted_to_tentative_parse_p (parser))
          error ("typedef-name %qD used as destructor declarator",
                 type_decl);

        return build_nt (BIT_NOT_EXPR, TREE_TYPE (type_decl));
      }

    case CPP_KEYWORD:
      if (token->keyword == RID_OPERATOR)
        {
          tree id;

          /* This could be a template-id, so we try that first.  */
          cp_parser_parse_tentatively (parser);
          /* Try a template-id.  */
          id = cp_parser_template_id (parser, template_keyword_p,
                                      /*check_dependency_p=*/true,
                                      declarator_p);
          /* If that worked, we're done.  */
          if (cp_parser_parse_definitely (parser))
            return id;
          /* We still don't know whether we're looking at an
             operator-function-id or a conversion-function-id.  */
          cp_parser_parse_tentatively (parser);
          /* Try an operator-function-id.  */
          id = cp_parser_operator_function_id (parser);
          /* If that didn't work, try a conversion-function-id.  */
          if (!cp_parser_parse_definitely (parser))
            id = cp_parser_conversion_function_id (parser);

          return id;
        }
      /* Fall through.  */

    default:
      cp_parser_error (parser, "expected unqualified-id");
      return error_mark_node;
    }
}

/* Parse an (optional) nested-name-specifier.

   nested-name-specifier:
     class-or-namespace-name :: nested-name-specifier [opt]
     class-or-namespace-name :: template nested-name-specifier [opt]

   PARSER->SCOPE should be set appropriately before this function is
   called.  TYPENAME_KEYWORD_P is TRUE if the `typename' keyword is in
   effect.  TYPE_P is TRUE if we non-type bindings should be ignored
   in name lookups.

   Sets PARSER->SCOPE to the class (TYPE) or namespace
   (NAMESPACE_DECL) specified by the nested-name-specifier, or leaves
   it unchanged if there is no nested-name-specifier.  Returns the new
   scope iff there is a nested-name-specifier, or NULL_TREE otherwise.

   If IS_DECLARATION is TRUE, the nested-name-specifier is known to be
   part of a declaration and/or decl-specifier.  */

static tree
cp_parser_nested_name_specifier_opt (cp_parser *parser,
                                     bool typename_keyword_p,
                                     bool check_dependency_p,
                                     bool type_p,
                                     bool is_declaration)
{
  bool success = false;
  tree access_check = NULL_TREE;
  cp_token_position start = 0;
  cp_token *token;

  /* If the next token corresponds to a nested name specifier, there
     is no need to reparse it.  However, if CHECK_DEPENDENCY_P is
     false, it may have been true before, in which case something
     like `A<X>::B<Y>::C' may have resulted in a nested-name-specifier
     of `A<X>::', where it should now be `A<X>::B<Y>::'.  So, when
     CHECK_DEPENDENCY_P is false, we have to fall through into the
     main loop.  */
  if (check_dependency_p
      && cp_lexer_next_token_is (parser->lexer, CPP_NESTED_NAME_SPECIFIER))
    {
      cp_parser_pre_parsed_nested_name_specifier (parser);
      return parser->scope;
    }

  /* Remember where the nested-name-specifier starts.  */
  if (cp_parser_uncommitted_to_tentative_parse_p (parser))
    start = cp_lexer_token_position (parser->lexer, false);

  push_deferring_access_checks (dk_deferred);

  while (true)
    {
      tree new_scope;
      tree old_scope;
      tree saved_qualifying_scope;
      bool template_keyword_p;

      /* Spot cases that cannot be the beginning of a
         nested-name-specifier.  */
      token = cp_lexer_peek_token (parser->lexer);

      /* If the next token is CPP_NESTED_NAME_SPECIFIER, just process
         the already parsed nested-name-specifier.  */
      if (token->type == CPP_NESTED_NAME_SPECIFIER)
        {
          /* Grab the nested-name-specifier and continue the loop.  */
          cp_parser_pre_parsed_nested_name_specifier (parser);
          success = true;
          continue;
        }

      /* Spot cases that cannot be the beginning of a
         nested-name-specifier.  On the second and subsequent times
         through the loop, we look for the `template' keyword.  */
      if (success && token->keyword == RID_TEMPLATE)
        ;
      /* A template-id can start a nested-name-specifier.  */
      else if (token->type == CPP_TEMPLATE_ID)
        ;
      else
        {
          /* If the next token is not an identifier, then it is
             definitely not a class-or-namespace-name.  */
          if (token->type != CPP_NAME)
            break;
          /* If the following token is neither a `<' (to begin a
             template-id), nor a `::', then we are not looking at a
             nested-name-specifier.  */
          token = cp_lexer_peek_nth_token (parser->lexer, 2);
          if (token->type != CPP_SCOPE
              && !cp_parser_nth_token_starts_template_argument_list_p
                  (parser, 2))
            break;
        }

      /* The nested-name-specifier is optional, so we parse
         tentatively.  */
      cp_parser_parse_tentatively (parser);

      /* Look for the optional `template' keyword, if this isn't the
         first time through the loop.  */
      if (success)
        template_keyword_p = cp_parser_optional_template_keyword (parser);
      else
        template_keyword_p = false;

      /* Save the old scope since the name lookup we are about to do
         might destroy it.  */
      old_scope = parser->scope;
      saved_qualifying_scope = parser->qualifying_scope;
      /* In a declarator-id like "X<T>::I::Y<T>" we must be able to
         look up names in "X<T>::I" in order to determine that "Y" is
         a template.  So, if we have a typename at this point, we make
         an effort to look through it.  */
      if (is_declaration
          && !typename_keyword_p
          && parser->scope
          && TREE_CODE (parser->scope) == TYPENAME_TYPE)
        parser->scope = resolve_typename_type (parser->scope,
                                               /*only_current_p=*/false);
      /* Parse the qualifying entity.  */
      new_scope
        = cp_parser_class_or_namespace_name (parser,
                                             typename_keyword_p,
                                             template_keyword_p,
                                             check_dependency_p,
                                             type_p,
                                             is_declaration);
      /* Look for the `::' token.  */
      cp_parser_require (parser, CPP_SCO