src/symtab.c

/* Symbol table manager for Bison,
   Copyright (C) 1984, 1989, 2000, 2001, 2002 Free Software Foundation, Inc.

   This file is part of Bison, the GNU Compiler Compiler.

   Bison 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.

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


#include "system.h"
#include "hash.h"
#include "complain.h"
#include "symtab.h"
#include "gram.h"

/*------------------------.
| Distinguished symbols.  |
`------------------------*/

symbol_t *errtoken = NULL;
symbol_t *undeftoken = NULL;
symbol_t *eoftoken = NULL;
symbol_t *axiom = NULL;
symbol_t *startsymbol = NULL;
location_t startsymbol_location;

/*---------------------------------.
| Create a new symbol, named TAG.  |
`---------------------------------*/

static symbol_t *
symbol_new (const char *tag, location_t location)
{
  symbol_t *res = XMALLOC (symbol_t, 1);

  res->tag = xstrdup (tag);
  res->type_name = NULL;
  res->location = location;
  res->number = NUMBER_UNDEFINED;
  res->prec = 0;
  res->assoc = right_assoc;
  res->user_token_number = USER_NUMBER_UNDEFINED;
  res->alias = NULL;
  res->class = unknown_sym;

  nsyms++;
  return res;
}


/*------------------------------------------------------------------.
| Set the TYPE_NAME associated to SYMBOL.  Does nothing if passed 0 |
| as TYPE_NAME.                                                     |
`------------------------------------------------------------------*/

void
symbol_type_set (symbol_t *symbol, char *type_name)
{
  if (type_name)
    {
      if (symbol->type_name)
	complain (_("type redeclaration for %s"), symbol->tag);
      symbol->type_name = type_name;
    }
}


/*------------------------------------------------------------------.
| Set the PRECEDENCE associated to SYMBOL.  Does nothing if invoked |
| with UNDEF_ASSOC as ASSOC.                                        |
`------------------------------------------------------------------*/

void
symbol_precedence_set (symbol_t *symbol,
		       int prec, associativity assoc)
{
  if (assoc != undef_assoc)
    {
      if (symbol->prec != 0)
	complain (_("redefining precedence of %s"), symbol->tag);
      symbol->prec = prec;
      symbol->assoc = assoc;
    }

  /* Only terminals have a precedence. */
  symbol_class_set (symbol, token_sym);
}


/*-------------------------------------.
| Set the CLASS associated to SYMBOL.  |
`-------------------------------------*/

void
symbol_class_set (symbol_t *symbol, symbol_class class)
{
  if (symbol->class != unknown_sym && symbol->class != class)
    complain (_("symbol %s redefined"), symbol->tag);

  if (class == nterm_sym && symbol->class != nterm_sym)
    symbol->number = nvars++;
  else if (class == token_sym && symbol->number == NUMBER_UNDEFINED)
    symbol->number = ntokens++;

  symbol->class = class;
}


/*-------------------------------------------------.
| Set the USER_TOKEN_NUMBER associated to SYMBOL.  |
`-------------------------------------------------*/

void
symbol_user_token_number_set (symbol_t *symbol, int user_token_number)
{
  assert (symbol->class == token_sym);

  if (symbol->user_token_number != USER_NUMBER_UNDEFINED
      && symbol->user_token_number != user_token_number)
    complain (_("redefining user token number of %s"), symbol->tag);

  symbol->user_token_number = user_token_number;
  /* User defined EOF token? */
  if (user_token_number == 0)
    {
      eoftoken = symbol;
      eoftoken->number = 0;
      /* It is always mapped to 0, so it was already counted in
	 NTOKENS.  */
      --ntokens;
    }
}


/*------------.
| Free THIS.  |
`------------*/

static void
symbol_free (symbol_t *this)
{
#if 0
  /* This causes crashes because one string can appear more
     than once.  */
  XFREE (this->type_name);
#endif
  XFREE (this->tag);
  XFREE (this);
}


/*-----------------------------------------------------------.
| If THIS is not defined, report an error, and consider it a |
| nonterminal.                                               |
`-----------------------------------------------------------*/

static bool
symbol_check_defined (symbol_t *this)
{
  if (this->class == unknown_sym)
    {
      complain_at
	(this->location,
	 _("symbol %s is used, but is not defined as a token and has no rules"),
	 this->tag);
      this->class = nterm_sym;
      this->number = nvars++;
    }

  return TRUE;
}


/*-------------------------------------------------------------------.
| Declare the new SYMBOL.  Make it an alias of SYMVAL, and type them |
| with TYPENAME.                                                     |
`-------------------------------------------------------------------*/

void
symbol_make_alias (symbol_t *symbol, symbol_t *symval)
{
  if (symval->alias)
    warn (_("symbol `%s' used more than once as a literal string"),
	  symval->tag);
  else if (symbol->alias)
    warn (_("symbol `%s' given more than one literal string"),
	  symbol->tag);
  else
    {
      symval->class = token_sym;
      symval->user_token_number = symbol->user_token_number;
      symbol->user_token_number = USER_NUMBER_ALIAS;
      symval->alias = symbol;
      symbol->alias = symval;
      /* symbol and symval combined are only one symbol */
      nsyms--;
      ntokens--;
      assert (ntokens == symbol->number || ntokens == symval->number);
      symbol->number = symval->number =
	(symval->number < symbol->number) ? symval->number : symbol->number;
    }
}


/*---------------------------------------------------------.
| Check that THIS, and its alias, have same precedence and |
| associativity.                                           |
`---------------------------------------------------------*/

static bool
symbol_check_alias_consistence (symbol_t *this)
{
  /* Check only those who _are_ the aliases. */
  if (this->alias && this->user_token_number == USER_NUMBER_ALIAS)
    {
      if (this->prec != this->alias->prec)
	{
	  if (this->prec != 0 && this->alias->prec != 0)
	    complain (_("conflicting precedences for %s and %s"),
		      this->tag, this->alias->tag);
	  if (this->prec != 0)
	    this->alias->prec = this->prec;
	  else
	    this->prec = this->alias->prec;
	}

      if (this->assoc != this->alias->assoc)
	{
	  /* FIXME: For some reason (probably the S/R => keep the S),
	     the right assoc is chosen has the ``not set''.  This is
	     not nice, fix this!  */
	  if (this->assoc != right_assoc
	      && this->alias->assoc != right_assoc)
	    complain (_("conflicting associativities for %s and %s"),
		      this->tag, this->alias->tag);
	  if (this->assoc != 0)
	    this->alias->assoc = this->assoc;
	  else
	    this->assoc = this->alias->assoc;
	}
    }
  return TRUE;
}


/*-------------------------------------------------------------------.
| Assign a symbol number, and write the definition of the token name |
| into FDEFINES.  Put in SYMBOLS.                                    |
`-------------------------------------------------------------------*/

static bool
symbol_pack (symbol_t *this)
{
  if (this->class == nterm_sym)
    {
      this->number += ntokens;
    }
  else if (this->alias)
    {
      /* This symbol and its alias are a single token defn.
	 Allocate a tokno, and assign to both check agreement of
	 prec and assoc fields and make both the same */
      if (this->number == NUMBER_UNDEFINED)
	{
	  if (this == eoftoken || this->alias == eoftoken)
	    this->number = this->alias->number = 0;
	  else
	    {
	      assert (this->alias->number != NUMBER_UNDEFINED);
	      this->number = this->alias->number;
	    }
	}
      /* Do not do processing below for USER_NUMBER_ALIASs.  */
      if (this->user_token_number == USER_NUMBER_ALIAS)
	return TRUE;
    }
  else /* this->class == token_sym */
    {
      assert (this->number != NUMBER_UNDEFINED);
    }

  symbols[this->number] = this;
  return TRUE;
}


/*--------------------------------------------------.
| Put THIS in TOKEN_TRANSLATIONS if it is a token.  |
`--------------------------------------------------*/

static bool
symbol_translation (symbol_t *this)
{
  /* Non-terminal? */
  if (this->class == token_sym
      && this->user_token_number != USER_NUMBER_ALIAS)
    {
      /* A token which translation has already been set? */
      if (token_translations[this->user_token_number] != undeftoken->number)
	complain (_("tokens %s and %s both assigned number %d"),
		  symbols[token_translations[this->user_token_number]]->tag,
		  this->tag, this->user_token_number);

      token_translations[this->user_token_number] = this->number;
    }

  return TRUE;
}


/*----------------------.
| A symbol hash table.  |
`----------------------*/

/* Initial capacity of symbols hash table.  */
#define HT_INITIAL_CAPACITY 257

static struct hash_table *symbol_table = NULL;

static bool
hash_compare_symbol_t (const symbol_t *m1, const symbol_t *m2)
{
  return strcmp (m1->tag, m2->tag) ? FALSE : TRUE;
}

static unsigned int
hash_symbol_t (const symbol_t *m, unsigned int tablesize)
{
  return hash_string (m->tag, tablesize);
}


/*-------------------------------.
| Create the symbol hash table.  |
`-------------------------------*/

void
symbols_new (void)
{
  symbol_table = hash_initialize (HT_INITIAL_CAPACITY,
				  NULL,
				  (Hash_hasher) hash_symbol_t,
				  (Hash_comparator) hash_compare_symbol_t,
				  (Hash_data_freer) symbol_free);
}


/*----------------------------------------------------------------.
| Find the symbol named KEY, and return it.  If it does not exist |
| yet, create it.                                                 |
`----------------------------------------------------------------*/

symbol_t *
getsym (const char *key, location_t location)
{
  symbol_t probe;
  symbol_t *entry;

  (const char *) probe.tag = key;
  entry = hash_lookup (symbol_table, &probe);

  if (!entry)
    {
      /* First insertion in the hash. */
      entry = symbol_new (key, location);
      hash_insert (symbol_table, entry);
    }
  return entry;
}


/*-------------------.
| Free the symbols.  |
`-------------------*/

void
symbols_free (void)
{
  hash_free (symbol_table);
}


/*---------------------------------------------------------------.
| Look for undefined symbols, report an error, and consider them |
| terminals.                                                     |
`---------------------------------------------------------------*/

void
symbols_do (symbol_processor processor, void *processor_data)
{
  hash_do_for_each (symbol_table,
		    (Hash_processor) processor,
		    processor_data);
}


/*--------------------------------------------------------------.
| Check that all the symbols are defined.  Report any undefined |
| symbols and consider them nonterminals.                       |
`--------------------------------------------------------------*/

void
symbols_check_defined (void)
{
  symbols_do (symbol_check_defined, NULL);
}

/*------------------------------------------------------------------.
| Set TOKEN_TRANSLATIONS.  Check that no two symbols share the same |
| number.                                                           |
`------------------------------------------------------------------*/

static void
symbols_token_translations_init (void)
{
  int num_256_available_p = TRUE;
  int i;

  /* Find the highest user token number, and whether 256, the POSIX
     preferred user token number for the error token, is used.  */
  max_user_token_number = 0;
  for (i = 0; i < ntokens; ++i)
    {
      symbol_t *this = symbols[i];
      if (this->user_token_number != USER_NUMBER_UNDEFINED)
	{
	  if (this->user_token_number > max_user_token_number)
	    max_user_token_number = this->user_token_number;
	  if (this->user_token_number == 256)
	    num_256_available_p = FALSE;
	}
    }

  /* If 256 is not used, assign it to error, to follow POSIX.  */
  if (num_256_available_p
      && errtoken->user_token_number == USER_NUMBER_UNDEFINED)
    errtoken->user_token_number = 256;

  /* Set the missing user numbers. */
  if (max_user_token_number < 256)
    max_user_token_number = 256;

  for (i = 0; i < ntokens; ++i)
    {
      symbol_t *this = symbols[i];
      if (this->user_token_number == USER_NUMBER_UNDEFINED)
	this->user_token_number = ++max_user_token_number;
      if (this->user_token_number > max_user_token_number)
	max_user_token_number = this->user_token_number;
    }

  token_translations = XCALLOC (symbol_number_t, max_user_token_number + 1);

  /* Initialize all entries for literal tokens to 2, the internal
     token number for $undefined., which represents all invalid
     inputs.  */
  for (i = 0; i < max_user_token_number + 1; i++)
    token_translations[i] = undeftoken->number;
  symbols_do (symbol_translation, NULL);
}


/*----------------------------------------------------------------.
| Assign symbol numbers, and write definition of token names into |
| FDEFINES.  Set up vectors SYMBOL_TABLE, TAGS of symbols.        |
`----------------------------------------------------------------*/

void
symbols_pack (void)
{
  symbols = XCALLOC (symbol_t *, nsyms);

  symbols_do (symbol_check_alias_consistence, NULL);
  symbols_do (symbol_pack, NULL);

  symbols_token_translations_init ();

  if (startsymbol->class == unknown_sym)
    fatal_at (startsymbol_location,
	      _("the start symbol %s is undefined"), startsymbol->tag);
  else if (startsymbol->class == token_sym)
    fatal_at (startsymbol_location,
	      _("the start symbol %s is a token"), startsymbol->tag);
}
Commit	Line	Data
	1	/* Symbol table manager for Bison,
	2	Copyright (C) 1984, 1989, 2000, 2001, 2002 Free Software Foundation, Inc.
	3
	4	This file is part of Bison, the GNU Compiler Compiler.
	5
	6	Bison is free software; you can redistribute it and/or modify
	7	it under the terms of the GNU General Public License as published by
	8	the Free Software Foundation; either version 2, or (at your option)
	9	any later version.
	10
	11	Bison is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with Bison; see the file COPYING. If not, write to
	18	the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	19	Boston, MA 02111-1307, USA. */
	20
	21
	22	#include "system.h"
	23	#include "hash.h"
	24	#include "complain.h"
	25	#include "symtab.h"
	26	#include "gram.h"
	27
	28	/*------------------------.
	29	\| Distinguished symbols. \|
	30	`------------------------*/
	31
	32	symbol_t *errtoken = NULL;
	33	symbol_t *undeftoken = NULL;
	34	symbol_t *eoftoken = NULL;
	35	symbol_t *axiom = NULL;
	36	symbol_t *startsymbol = NULL;
	37	location_t startsymbol_location;
	38
	39	/*---------------------------------.
	40	\| Create a new symbol, named TAG. \|
	41	`---------------------------------*/
	42
	43	static symbol_t *
	44	symbol_new (const char *tag, location_t location)
	45	{
	46	symbol_t *res = XMALLOC (symbol_t, 1);
	47
	48	res->tag = xstrdup (tag);
	49	res->type_name = NULL;
	50	res->location = location;
	51	res->number = NUMBER_UNDEFINED;
	52	res->prec = 0;
	53	res->assoc = right_assoc;
	54	res->user_token_number = USER_NUMBER_UNDEFINED;
	55	res->alias = NULL;
	56	res->class = unknown_sym;
	57
	58	nsyms++;
	59	return res;
	60	}
	61
	62
	63	/*------------------------------------------------------------------.
	64	\| Set the TYPE_NAME associated to SYMBOL. Does nothing if passed 0 \|
	65	\| as TYPE_NAME. \|
	66	`------------------------------------------------------------------*/
	67
	68	void
	69	symbol_type_set (symbol_t symbol, char type_name)
	70	{
	71	if (type_name)
	72	{
	73	if (symbol->type_name)
	74	complain (_("type redeclaration for %s"), symbol->tag);
	75	symbol->type_name = type_name;
	76	}
	77	}
	78
	79
	80	/*------------------------------------------------------------------.
	81	\| Set the PRECEDENCE associated to SYMBOL. Does nothing if invoked \|
	82	\| with UNDEF_ASSOC as ASSOC. \|
	83	`------------------------------------------------------------------*/
	84
	85	void
	86	symbol_precedence_set (symbol_t *symbol,
	87	int prec, associativity assoc)
	88	{
	89	if (assoc != undef_assoc)
	90	{
	91	if (symbol->prec != 0)
	92	complain (_("redefining precedence of %s"), symbol->tag);
	93	symbol->prec = prec;
	94	symbol->assoc = assoc;
	95	}
	96
	97	/* Only terminals have a precedence. */
	98	symbol_class_set (symbol, token_sym);
	99	}
	100
	101
	102	/*-------------------------------------.
	103	\| Set the CLASS associated to SYMBOL. \|
	104	`-------------------------------------*/
	105
	106	void
	107	symbol_class_set (symbol_t *symbol, symbol_class class)
	108	{
	109	if (symbol->class != unknown_sym && symbol->class != class)
	110	complain (_("symbol %s redefined"), symbol->tag);
	111
	112	if (class == nterm_sym && symbol->class != nterm_sym)
	113	symbol->number = nvars++;
	114	else if (class == token_sym && symbol->number == NUMBER_UNDEFINED)
	115	symbol->number = ntokens++;
	116
	117	symbol->class = class;
	118	}
	119
	120
	121	/*-------------------------------------------------.
	122	\| Set the USER_TOKEN_NUMBER associated to SYMBOL. \|
	123	`-------------------------------------------------*/
	124
	125	void
	126	symbol_user_token_number_set (symbol_t *symbol, int user_token_number)
	127	{
	128	assert (symbol->class == token_sym);
	129
	130	if (symbol->user_token_number != USER_NUMBER_UNDEFINED
	131	&& symbol->user_token_number != user_token_number)
	132	complain (_("redefining user token number of %s"), symbol->tag);
	133
	134	symbol->user_token_number = user_token_number;
	135	/* User defined EOF token? */
	136	if (user_token_number == 0)
	137	{
	138	eoftoken = symbol;
	139	eoftoken->number = 0;
	140	/* It is always mapped to 0, so it was already counted in
	141	NTOKENS. */
	142	--ntokens;
	143	}
	144	}
	145
	146
	147	/*------------.
	148	\| Free THIS. \|
	149	`------------*/
	150
	151	static void
	152	symbol_free (symbol_t *this)
	153	{
	154	#if 0
	155	/* This causes crashes because one string can appear more
	156	than once. */
	157	XFREE (this->type_name);
	158	#endif
	159	XFREE (this->tag);
	160	XFREE (this);
	161	}
	162
	163
	164	/*-----------------------------------------------------------.
	165	\| If THIS is not defined, report an error, and consider it a \|
	166	\| nonterminal. \|
	167	`-----------------------------------------------------------*/
	168
	169	static bool
	170	symbol_check_defined (symbol_t *this)
	171	{
	172	if (this->class == unknown_sym)
	173	{
	174	complain_at
	175	(this->location,
	176	_("symbol %s is used, but is not defined as a token and has no rules"),
	177	this->tag);
	178	this->class = nterm_sym;
	179	this->number = nvars++;
	180	}
	181
	182	return TRUE;
	183	}
	184
	185
	186	/*-------------------------------------------------------------------.
	187	\| Declare the new SYMBOL. Make it an alias of SYMVAL, and type them \|
	188	\| with TYPENAME. \|
	189	`-------------------------------------------------------------------*/
	190
	191	void
	192	symbol_make_alias (symbol_t symbol, symbol_t symval)
	193	{
	194	if (symval->alias)
	195	warn (_("symbol `%s' used more than once as a literal string"),
	196	symval->tag);
	197	else if (symbol->alias)
	198	warn (_("symbol `%s' given more than one literal string"),
	199	symbol->tag);
	200	else
	201	{
	202	symval->class = token_sym;
	203	symval->user_token_number = symbol->user_token_number;
	204	symbol->user_token_number = USER_NUMBER_ALIAS;
	205	symval->alias = symbol;
	206	symbol->alias = symval;
	207	/* symbol and symval combined are only one symbol */
	208	nsyms--;
	209	ntokens--;
	210	assert (ntokens == symbol->number \|\| ntokens == symval->number);
	211	symbol->number = symval->number =
	212	(symval->number < symbol->number) ? symval->number : symbol->number;
	213	}
	214	}
	215
	216
	217	/*---------------------------------------------------------.
	218	\| Check that THIS, and its alias, have same precedence and \|
	219	\| associativity. \|
	220	`---------------------------------------------------------*/
	221
	222	static bool
	223	symbol_check_alias_consistence (symbol_t *this)
	224	{
	225	/* Check only those who _are_ the aliases. */
	226	if (this->alias && this->user_token_number == USER_NUMBER_ALIAS)
	227	{
	228	if (this->prec != this->alias->prec)
	229	{
	230	if (this->prec != 0 && this->alias->prec != 0)
	231	complain (_("conflicting precedences for %s and %s"),
	232	this->tag, this->alias->tag);
	233	if (this->prec != 0)
	234	this->alias->prec = this->prec;
	235	else
	236	this->prec = this->alias->prec;
	237	}
	238
	239	if (this->assoc != this->alias->assoc)
	240	{
	241	/* FIXME: For some reason (probably the S/R => keep the S),
	242	the right assoc is chosen has the ``not set''. This is
	243	not nice, fix this! */
	244	if (this->assoc != right_assoc
	245	&& this->alias->assoc != right_assoc)
	246	complain (_("conflicting associativities for %s and %s"),
	247	this->tag, this->alias->tag);
	248	if (this->assoc != 0)
	249	this->alias->assoc = this->assoc;
	250	else
	251	this->assoc = this->alias->assoc;
	252	}
	253	}
	254	return TRUE;
	255	}
	256
	257
	258	/*-------------------------------------------------------------------.
	259	\| Assign a symbol number, and write the definition of the token name \|
	260	\| into FDEFINES. Put in SYMBOLS. \|
	261	`-------------------------------------------------------------------*/
	262
	263	static bool
	264	symbol_pack (symbol_t *this)
	265	{
	266	if (this->class == nterm_sym)
	267	{
	268	this->number += ntokens;
	269	}
	270	else if (this->alias)
	271	{
	272	/* This symbol and its alias are a single token defn.
	273	Allocate a tokno, and assign to both check agreement of
	274	prec and assoc fields and make both the same */
	275	if (this->number == NUMBER_UNDEFINED)
	276	{
	277	if (this == eoftoken \|\| this->alias == eoftoken)
	278	this->number = this->alias->number = 0;
	279	else
	280	{
	281	assert (this->alias->number != NUMBER_UNDEFINED);
	282	this->number = this->alias->number;
	283	}
	284	}
	285	/* Do not do processing below for USER_NUMBER_ALIASs. */
	286	if (this->user_token_number == USER_NUMBER_ALIAS)
	287	return TRUE;
	288	}
	289	else /* this->class == token_sym */
	290	{
	291	assert (this->number != NUMBER_UNDEFINED);
	292	}
	293
	294	symbols[this->number] = this;
	295	return TRUE;
	296	}
	297
	298
	299
	300
	301	/*--------------------------------------------------.
	302	\| Put THIS in TOKEN_TRANSLATIONS if it is a token. \|
	303	`--------------------------------------------------*/
	304
	305	static bool
	306	symbol_translation (symbol_t *this)
	307	{
	308	/* Non-terminal? */
	309	if (this->class == token_sym
	310	&& this->user_token_number != USER_NUMBER_ALIAS)
	311	{
	312	/* A token which translation has already been set? */
	313	if (token_translations[this->user_token_number] != undeftoken->number)
	314	complain (_("tokens %s and %s both assigned number %d"),
	315	symbols[token_translations[this->user_token_number]]->tag,
	316	this->tag, this->user_token_number);
	317
	318	token_translations[this->user_token_number] = this->number;
	319	}
	320
	321	return TRUE;
	322	}
	323
	324
	325	/*----------------------.
	326	\| A symbol hash table. \|
	327	`----------------------*/
	328
	329	/* Initial capacity of symbols hash table. */
	330	#define HT_INITIAL_CAPACITY 257
	331
	332	static struct hash_table *symbol_table = NULL;
	333
	334	static bool
	335	hash_compare_symbol_t (const symbol_t m1, const symbol_t m2)
	336	{
	337	return strcmp (m1->tag, m2->tag) ? FALSE : TRUE;
	338	}
	339
	340	static unsigned int
	341	hash_symbol_t (const symbol_t *m, unsigned int tablesize)
	342	{
	343	return hash_string (m->tag, tablesize);
	344	}
	345
	346
	347	/*-------------------------------.
	348	\| Create the symbol hash table. \|
	349	`-------------------------------*/
	350
	351	void
	352	symbols_new (void)
	353	{
	354	symbol_table = hash_initialize (HT_INITIAL_CAPACITY,
	355	NULL,
	356	(Hash_hasher) hash_symbol_t,
	357	(Hash_comparator) hash_compare_symbol_t,
	358	(Hash_data_freer) symbol_free);
	359	}
	360
	361
	362	/*----------------------------------------------------------------.
	363	\| Find the symbol named KEY, and return it. If it does not exist \|
	364	\| yet, create it. \|
	365	`----------------------------------------------------------------*/
	366
	367	symbol_t *
	368	getsym (const char *key, location_t location)
	369	{
	370	symbol_t probe;
	371	symbol_t *entry;
	372
	373	(const char *) probe.tag = key;
	374	entry = hash_lookup (symbol_table, &probe);
	375
	376	if (!entry)
	377	{
	378	/* First insertion in the hash. */
	379	entry = symbol_new (key, location);
	380	hash_insert (symbol_table, entry);
	381	}
	382	return entry;
	383	}
	384
	385
	386	/*-------------------.
	387	\| Free the symbols. \|
	388	`-------------------*/
	389
	390	void
	391	symbols_free (void)
	392	{
	393	hash_free (symbol_table);
	394	}
	395
	396
	397	/*---------------------------------------------------------------.
	398	\| Look for undefined symbols, report an error, and consider them \|
	399	\| terminals. \|
	400	`---------------------------------------------------------------*/
	401
	402	void
	403	symbols_do (symbol_processor processor, void *processor_data)
	404	{
	405	hash_do_for_each (symbol_table,
	406	(Hash_processor) processor,
	407	processor_data);
	408	}
	409
	410
	411	/*--------------------------------------------------------------.
	412	\| Check that all the symbols are defined. Report any undefined \|
	413	\| symbols and consider them nonterminals. \|
	414	`--------------------------------------------------------------*/
	415
	416	void
	417	symbols_check_defined (void)
	418	{
	419	symbols_do (symbol_check_defined, NULL);
	420	}
	421
	422	/*------------------------------------------------------------------.
	423	\| Set TOKEN_TRANSLATIONS. Check that no two symbols share the same \|
	424	\| number. \|
	425	`------------------------------------------------------------------*/
	426
	427	static void
	428	symbols_token_translations_init (void)
	429	{
	430	int num_256_available_p = TRUE;
	431	int i;
	432
	433	/* Find the highest user token number, and whether 256, the POSIX
	434	preferred user token number for the error token, is used. */
	435	max_user_token_number = 0;
	436	for (i = 0; i < ntokens; ++i)
	437	{
	438	symbol_t *this = symbols[i];
	439	if (this->user_token_number != USER_NUMBER_UNDEFINED)
	440	{
	441	if (this->user_token_number > max_user_token_number)
	442	max_user_token_number = this->user_token_number;
	443	if (this->user_token_number == 256)
	444	num_256_available_p = FALSE;
	445	}
	446	}
	447
	448	/* If 256 is not used, assign it to error, to follow POSIX. */
	449	if (num_256_available_p
	450	&& errtoken->user_token_number == USER_NUMBER_UNDEFINED)
	451	errtoken->user_token_number = 256;
	452
	453	/* Set the missing user numbers. */
	454	if (max_user_token_number < 256)
	455	max_user_token_number = 256;
	456
	457	for (i = 0; i < ntokens; ++i)
	458	{
	459	symbol_t *this = symbols[i];
	460	if (this->user_token_number == USER_NUMBER_UNDEFINED)
	461	this->user_token_number = ++max_user_token_number;
	462	if (this->user_token_number > max_user_token_number)
	463	max_user_token_number = this->user_token_number;
	464	}
	465
	466	token_translations = XCALLOC (symbol_number_t, max_user_token_number + 1);
	467
	468	/* Initialize all entries for literal tokens to 2, the internal
	469	token number for $undefined., which represents all invalid
	470	inputs. */
	471	for (i = 0; i < max_user_token_number + 1; i++)
	472	token_translations[i] = undeftoken->number;
	473	symbols_do (symbol_translation, NULL);
	474	}
	475
	476
	477	/*----------------------------------------------------------------.
	478	\| Assign symbol numbers, and write definition of token names into \|
	479	\| FDEFINES. Set up vectors SYMBOL_TABLE, TAGS of symbols. \|
	480	`----------------------------------------------------------------*/
	481
	482	void
	483	symbols_pack (void)
	484	{
	485	symbols = XCALLOC (symbol_t *, nsyms);
	486
	487	symbols_do (symbol_check_alias_consistence, NULL);
	488	symbols_do (symbol_pack, NULL);
	489
	490	symbols_token_translations_init ();
	491
	492	if (startsymbol->class == unknown_sym)
	493	fatal_at (startsymbol_location,
	494	_("the start symbol %s is undefined"), startsymbol->tag);
	495	else if (startsymbol->class == token_sym)
	496	fatal_at (startsymbol_location,
	497	_("the start symbol %s is a token"), startsymbol->tag);
	498	}