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 "quotearg.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->destructor = 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;
}


/*-----------------------------------------------------------------.
| Return the tag of this SYMBOL in a printable form.  Warning: use |
| the first QUOTEARG slot: 0.                                      |
`-----------------------------------------------------------------*/

const char *
symbol_tag_get (symbol_t *symbol)
{
  return quotearg_style (escape_quoting_style, symbol->tag);
}


/*------------------------------------------------------------.
| Return the tag of this SYMBOL in a printable form.  Use the |
| QUOTEARG slot number N.                                     |
`------------------------------------------------------------*/

const char *
symbol_tag_get_n (symbol_t *symbol, int n)
{
  return quotearg_n_style (n, escape_quoting_style, symbol->tag);
}


/*-------------------------------.
| Print the tag of this SYMBOL.  |
`-------------------------------*/

void
symbol_tag_print (symbol_t *symbol, FILE *out)
{
  fputs (symbol_tag_get (symbol), out);
}


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

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


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

void
symbol_destructor_set (symbol_t *symbol, location_t location, char *destructor)
{
  if (destructor)
    {
      if (symbol->destructor)
	complain_at (location,
		     _("destructor redeclaration for %s"),
		     symbol_tag_get (symbol));
      symbol->destructor = destructor;
    }
}


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

void
symbol_precedence_set (symbol_t *symbol, location_t location,
		       int prec, associativity assoc)
{
  if (assoc != undef_assoc)
    {
      if (symbol->prec != 0)
	complain_at (location,
		     _("redefining precedence of %s"),
		     symbol_tag_get (symbol));
      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_get (symbol));

  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_get (symbol));

  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"),
	 symbol_tag_get (this));
      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"),
	  symbol_tag_get (symval));
  else if (symbol->alias)
    warn (_("symbol `%s' given more than one literal string"),
	  symbol_tag_get (symbol));
  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"),
		      symbol_tag_get (this), symbol_tag_get (this->alias));
	  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"),
		      symbol_tag_get (this), symbol_tag_get (this->alias));
	  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"),
		  symbol_tag_get (symbols[token_translations[this->user_token_number]]),
		  symbol_tag_get (this), 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"),
	      symbol_tag_get (startsymbol));
  else if (startsymbol->class == token_sym)
    fatal_at (startsymbol_location,
	      _("the start symbol %s is a token"),
	      symbol_tag_get (startsymbol));
}
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 "quotearg.h"
	24	#include "hash.h"
	25	#include "complain.h"
	26	#include "symtab.h"
	27	#include "gram.h"
	28
	29	/*------------------------.
	30	\| Distinguished symbols. \|
	31	`------------------------*/
	32
	33	symbol_t *errtoken = NULL;
	34	symbol_t *undeftoken = NULL;
	35	symbol_t *eoftoken = NULL;
	36	symbol_t *axiom = NULL;
	37	symbol_t *startsymbol = NULL;
	38	location_t startsymbol_location;
	39
	40	/*---------------------------------.
	41	\| Create a new symbol, named TAG. \|
	42	`---------------------------------*/
	43
	44	static symbol_t *
	45	symbol_new (const char *tag, location_t location)
	46	{
	47	symbol_t *res = XMALLOC (symbol_t, 1);
	48
	49	res->tag = xstrdup (tag);
	50	res->type_name = NULL;
	51	res->destructor = NULL;
	52	res->location = location;
	53	res->number = NUMBER_UNDEFINED;
	54	res->prec = 0;
	55	res->assoc = right_assoc;
	56	res->user_token_number = USER_NUMBER_UNDEFINED;
	57	res->alias = NULL;
	58	res->class = unknown_sym;
	59
	60	nsyms++;
	61	return res;
	62	}
	63
	64
	65	/*-----------------------------------------------------------------.
	66	\| Return the tag of this SYMBOL in a printable form. Warning: use \|
	67	\| the first QUOTEARG slot: 0. \|
	68	`-----------------------------------------------------------------*/
	69
	70	const char *
	71	symbol_tag_get (symbol_t *symbol)
	72	{
	73	return quotearg_style (escape_quoting_style, symbol->tag);
	74	}
	75
	76
	77	/*------------------------------------------------------------.
	78	\| Return the tag of this SYMBOL in a printable form. Use the \|
	79	\| QUOTEARG slot number N. \|
	80	`------------------------------------------------------------*/
	81
	82	const char *
	83	symbol_tag_get_n (symbol_t *symbol, int n)
	84	{
	85	return quotearg_n_style (n, escape_quoting_style, symbol->tag);
	86	}
	87
	88
	89	/*-------------------------------.
	90	\| Print the tag of this SYMBOL. \|
	91	`-------------------------------*/
	92
	93	void
	94	symbol_tag_print (symbol_t symbol, FILE out)
	95	{
	96	fputs (symbol_tag_get (symbol), out);
	97	}
	98
	99
	100	/*------------------------------------------------------------------.
	101	\| Set the TYPE_NAME associated to SYMBOL. Does nothing if passed 0 \|
	102	\| as TYPE_NAME. \|
	103	`------------------------------------------------------------------*/
	104
	105	void
	106	symbol_type_set (symbol_t symbol, location_t location, char type_name)
	107	{
	108	if (type_name)
	109	{
	110	if (symbol->type_name)
	111	complain_at (location,
	112	_("type redeclaration for %s"), symbol_tag_get (symbol));
	113	symbol->type_name = type_name;
	114	}
	115	}
	116
	117
	118	/*-------------------------------------------------------------------.
	119	\| Set the DESTRUCTOR associated to SYMBOL. Does nothing if passed 0 \|
	120	\| as DESTRUCTOR. \|
	121	`-------------------------------------------------------------------*/
	122
	123	void
	124	symbol_destructor_set (symbol_t symbol, location_t location, char destructor)
	125	{
	126	if (destructor)
	127	{
	128	if (symbol->destructor)
	129	complain_at (location,
	130	_("destructor redeclaration for %s"),
	131	symbol_tag_get (symbol));
	132	symbol->destructor = destructor;
	133	}
	134	}
	135
	136
	137	/*------------------------------------------------------------------.
	138	\| Set the PRECEDENCE associated to SYMBOL. Does nothing if invoked \|
	139	\| with UNDEF_ASSOC as ASSOC. \|
	140	`------------------------------------------------------------------*/
	141
	142	void
	143	symbol_precedence_set (symbol_t *symbol, location_t location,
	144	int prec, associativity assoc)
	145	{
	146	if (assoc != undef_assoc)
	147	{
	148	if (symbol->prec != 0)
	149	complain_at (location,
	150	_("redefining precedence of %s"),
	151	symbol_tag_get (symbol));
	152	symbol->prec = prec;
	153	symbol->assoc = assoc;
	154	}
	155
	156	/* Only terminals have a precedence. */
	157	symbol_class_set (symbol, token_sym);
	158	}
	159
	160
	161	/*-------------------------------------.
	162	\| Set the CLASS associated to SYMBOL. \|
	163	`-------------------------------------*/
	164
	165	void
	166	symbol_class_set (symbol_t *symbol, symbol_class class)
	167	{
	168	if (symbol->class != unknown_sym && symbol->class != class)
	169	complain (_("symbol %s redefined"), symbol_tag_get (symbol));
	170
	171	if (class == nterm_sym && symbol->class != nterm_sym)
	172	symbol->number = nvars++;
	173	else if (class == token_sym && symbol->number == NUMBER_UNDEFINED)
	174	symbol->number = ntokens++;
	175
	176	symbol->class = class;
	177	}
	178
	179
	180	/*-------------------------------------------------.
	181	\| Set the USER_TOKEN_NUMBER associated to SYMBOL. \|
	182	`-------------------------------------------------*/
	183
	184	void
	185	symbol_user_token_number_set (symbol_t *symbol, int user_token_number)
	186	{
	187	assert (symbol->class == token_sym);
	188
	189	if (symbol->user_token_number != USER_NUMBER_UNDEFINED
	190	&& symbol->user_token_number != user_token_number)
	191	complain (_("redefining user token number of %s"),
	192	symbol_tag_get (symbol));
	193
	194	symbol->user_token_number = user_token_number;
	195	/* User defined EOF token? */
	196	if (user_token_number == 0)
	197	{
	198	eoftoken = symbol;
	199	eoftoken->number = 0;
	200	/* It is always mapped to 0, so it was already counted in
	201	NTOKENS. */
	202	--ntokens;
	203	}
	204	}
	205
	206
	207	/*------------.
	208	\| Free THIS. \|
	209	`------------*/
	210
	211	static void
	212	symbol_free (symbol_t *this)
	213	{
	214	#if 0
	215	/* This causes crashes because one string can appear more
	216	than once. */
	217	XFREE (this->type_name);
	218	#endif
	219	XFREE (this->tag);
	220	XFREE (this);
	221	}
	222
	223
	224	/*-----------------------------------------------------------.
	225	\| If THIS is not defined, report an error, and consider it a \|
	226	\| nonterminal. \|
	227	`-----------------------------------------------------------*/
	228
	229	static bool
	230	symbol_check_defined (symbol_t *this)
	231	{
	232	if (this->class == unknown_sym)
	233	{
	234	complain_at
	235	(this->location,
	236	_("symbol %s is used, but is not defined as a token and has no rules"),
	237	symbol_tag_get (this));
	238	this->class = nterm_sym;
	239	this->number = nvars++;
	240	}
	241
	242	return TRUE;
	243	}
	244
	245
	246	/*-------------------------------------------------------------------.
	247	\| Declare the new SYMBOL. Make it an alias of SYMVAL, and type them \|
	248	\| with TYPENAME. \|
	249	`-------------------------------------------------------------------*/
	250
	251	void
	252	symbol_make_alias (symbol_t symbol, symbol_t symval)
	253	{
	254	if (symval->alias)
	255	warn (_("symbol `%s' used more than once as a literal string"),
	256	symbol_tag_get (symval));
	257	else if (symbol->alias)
	258	warn (_("symbol `%s' given more than one literal string"),
	259	symbol_tag_get (symbol));
	260	else
	261	{
	262	symval->class = token_sym;
	263	symval->user_token_number = symbol->user_token_number;
	264	symbol->user_token_number = USER_NUMBER_ALIAS;
	265	symval->alias = symbol;
	266	symbol->alias = symval;
	267	/* symbol and symval combined are only one symbol */
	268	nsyms--;
	269	ntokens--;
	270	assert (ntokens == symbol->number \|\| ntokens == symval->number);
	271	symbol->number = symval->number =
	272	(symval->number < symbol->number) ? symval->number : symbol->number;
	273	}
	274	}
	275
	276
	277	/*---------------------------------------------------------.
	278	\| Check that THIS, and its alias, have same precedence and \|
	279	\| associativity. \|
	280	`---------------------------------------------------------*/
	281
	282	static bool
	283	symbol_check_alias_consistence (symbol_t *this)
	284	{
	285	/* Check only those who _are_ the aliases. */
	286	if (this->alias && this->user_token_number == USER_NUMBER_ALIAS)
	287	{
	288	if (this->prec != this->alias->prec)
	289	{
	290	if (this->prec != 0 && this->alias->prec != 0)
	291	complain (_("conflicting precedences for %s and %s"),
	292	symbol_tag_get (this), symbol_tag_get (this->alias));
	293	if (this->prec != 0)
	294	this->alias->prec = this->prec;
	295	else
	296	this->prec = this->alias->prec;
	297	}
	298
	299	if (this->assoc != this->alias->assoc)
	300	{
	301	/* FIXME: For some reason (probably the S/R => keep the S),
	302	the right assoc is chosen has the ``not set''. This is
	303	not nice, fix this! */
	304	if (this->assoc != right_assoc
	305	&& this->alias->assoc != right_assoc)
	306	complain (_("conflicting associativities for %s and %s"),
	307	symbol_tag_get (this), symbol_tag_get (this->alias));
	308	if (this->assoc != 0)
	309	this->alias->assoc = this->assoc;
	310	else
	311	this->assoc = this->alias->assoc;
	312	}
	313	}
	314	return TRUE;
	315	}
	316
	317
	318	/*-------------------------------------------------------------------.
	319	\| Assign a symbol number, and write the definition of the token name \|
	320	\| into FDEFINES. Put in SYMBOLS. \|
	321	`-------------------------------------------------------------------*/
	322
	323	static bool
	324	symbol_pack (symbol_t *this)
	325	{
	326	if (this->class == nterm_sym)
	327	{
	328	this->number += ntokens;
	329	}
	330	else if (this->alias)
	331	{
	332	/* This symbol and its alias are a single token defn.
	333	Allocate a tokno, and assign to both check agreement of
	334	prec and assoc fields and make both the same */
	335	if (this->number == NUMBER_UNDEFINED)
	336	{
	337	if (this == eoftoken \|\| this->alias == eoftoken)
	338	this->number = this->alias->number = 0;
	339	else
	340	{
	341	assert (this->alias->number != NUMBER_UNDEFINED);
	342	this->number = this->alias->number;
	343	}
	344	}
	345	/* Do not do processing below for USER_NUMBER_ALIASs. */
	346	if (this->user_token_number == USER_NUMBER_ALIAS)
	347	return TRUE;
	348	}
	349	else /* this->class == token_sym */
	350	{
	351	assert (this->number != NUMBER_UNDEFINED);
	352	}
	353
	354	symbols[this->number] = this;
	355	return TRUE;
	356	}
	357
	358
	359
	360
	361	/*--------------------------------------------------.
	362	\| Put THIS in TOKEN_TRANSLATIONS if it is a token. \|
	363	`--------------------------------------------------*/
	364
	365	static bool
	366	symbol_translation (symbol_t *this)
	367	{
	368	/* Non-terminal? */
	369	if (this->class == token_sym
	370	&& this->user_token_number != USER_NUMBER_ALIAS)
	371	{
	372	/* A token which translation has already been set? */
	373	if (token_translations[this->user_token_number] != undeftoken->number)
	374	complain (_("tokens %s and %s both assigned number %d"),
	375	symbol_tag_get (symbols[token_translations[this->user_token_number]]),
	376	symbol_tag_get (this), this->user_token_number);
	377
	378	token_translations[this->user_token_number] = this->number;
	379	}
	380
	381	return TRUE;
	382	}
	383
	384
	385	/*----------------------.
	386	\| A symbol hash table. \|
	387	`----------------------*/
	388
	389	/* Initial capacity of symbols hash table. */
	390	#define HT_INITIAL_CAPACITY 257
	391
	392	static struct hash_table *symbol_table = NULL;
	393
	394	static bool
	395	hash_compare_symbol_t (const symbol_t m1, const symbol_t m2)
	396	{
	397	return strcmp (m1->tag, m2->tag) ? FALSE : TRUE;
	398	}
	399
	400	static unsigned int
	401	hash_symbol_t (const symbol_t *m, unsigned int tablesize)
	402	{
	403	return hash_string (m->tag, tablesize);
	404	}
	405
	406
	407	/*-------------------------------.
	408	\| Create the symbol hash table. \|
	409	`-------------------------------*/
	410
	411	void
	412	symbols_new (void)
	413	{
	414	symbol_table = hash_initialize (HT_INITIAL_CAPACITY,
	415	NULL,
	416	(Hash_hasher) hash_symbol_t,
	417	(Hash_comparator) hash_compare_symbol_t,
	418	(Hash_data_freer) symbol_free);
	419	}
	420
	421
	422	/*----------------------------------------------------------------.
	423	\| Find the symbol named KEY, and return it. If it does not exist \|
	424	\| yet, create it. \|
	425	`----------------------------------------------------------------*/
	426
	427	symbol_t *
	428	getsym (const char *key, location_t location)
	429	{
	430	symbol_t probe;
	431	symbol_t *entry;
	432
	433	(const char *) probe.tag = key;
	434	entry = hash_lookup (symbol_table, &probe);
	435
	436	if (!entry)
	437	{
	438	/* First insertion in the hash. */
	439	entry = symbol_new (key, location);
	440	hash_insert (symbol_table, entry);
	441	}
	442	return entry;
	443	}
	444
	445
	446	/*-------------------.
	447	\| Free the symbols. \|
	448	`-------------------*/
	449
	450	void
	451	symbols_free (void)
	452	{
	453	hash_free (symbol_table);
	454	}
	455
	456
	457	/*---------------------------------------------------------------.
	458	\| Look for undefined symbols, report an error, and consider them \|
	459	\| terminals. \|
	460	`---------------------------------------------------------------*/
	461
	462	void
	463	symbols_do (symbol_processor processor, void *processor_data)
	464	{
	465	hash_do_for_each (symbol_table,
	466	(Hash_processor) processor,
	467	processor_data);
	468	}
	469
	470
	471	/*--------------------------------------------------------------.
	472	\| Check that all the symbols are defined. Report any undefined \|
	473	\| symbols and consider them nonterminals. \|
	474	`--------------------------------------------------------------*/
	475
	476	void
	477	symbols_check_defined (void)
	478	{
	479	symbols_do (symbol_check_defined, NULL);
	480	}
	481
	482	/*------------------------------------------------------------------.
	483	\| Set TOKEN_TRANSLATIONS. Check that no two symbols share the same \|
	484	\| number. \|
	485	`------------------------------------------------------------------*/
	486
	487	static void
	488	symbols_token_translations_init (void)
	489	{
	490	int num_256_available_p = TRUE;
	491	int i;
	492
	493	/* Find the highest user token number, and whether 256, the POSIX
	494	preferred user token number for the error token, is used. */
	495	max_user_token_number = 0;
	496	for (i = 0; i < ntokens; ++i)
	497	{
	498	symbol_t *this = symbols[i];
	499	if (this->user_token_number != USER_NUMBER_UNDEFINED)
	500	{
	501	if (this->user_token_number > max_user_token_number)
	502	max_user_token_number = this->user_token_number;
	503	if (this->user_token_number == 256)
	504	num_256_available_p = FALSE;
	505	}
	506	}
	507
	508	/* If 256 is not used, assign it to error, to follow POSIX. */
	509	if (num_256_available_p
	510	&& errtoken->user_token_number == USER_NUMBER_UNDEFINED)
	511	errtoken->user_token_number = 256;
	512
	513	/* Set the missing user numbers. */
	514	if (max_user_token_number < 256)
	515	max_user_token_number = 256;
	516
	517	for (i = 0; i < ntokens; ++i)
	518	{
	519	symbol_t *this = symbols[i];
	520	if (this->user_token_number == USER_NUMBER_UNDEFINED)
	521	this->user_token_number = ++max_user_token_number;
	522	if (this->user_token_number > max_user_token_number)
	523	max_user_token_number = this->user_token_number;
	524	}
	525
	526	token_translations = XCALLOC (symbol_number_t, max_user_token_number + 1);
	527
	528	/* Initialize all entries for literal tokens to 2, the internal
	529	token number for $undefined., which represents all invalid
	530	inputs. */
	531	for (i = 0; i < max_user_token_number + 1; i++)
	532	token_translations[i] = undeftoken->number;
	533	symbols_do (symbol_translation, NULL);
	534	}
	535
	536
	537	/*----------------------------------------------------------------.
	538	\| Assign symbol numbers, and write definition of token names into \|
	539	\| FDEFINES. Set up vectors SYMBOL_TABLE, TAGS of symbols. \|
	540	`----------------------------------------------------------------*/
	541
	542	void
	543	symbols_pack (void)
	544	{
	545	symbols = XCALLOC (symbol_t *, nsyms);
	546
	547	symbols_do (symbol_check_alias_consistence, NULL);
	548	symbols_do (symbol_pack, NULL);
	549
	550	symbols_token_translations_init ();
	551
	552	if (startsymbol->class == unknown_sym)
	553	fatal_at (startsymbol_location,
	554	_("the start symbol %s is undefined"),
	555	symbol_tag_get (startsymbol));
	556	else if (startsymbol->class == token_sym)
	557	fatal_at (startsymbol_location,
	558	_("the start symbol %s is a token"),
	559	symbol_tag_get (startsymbol));
	560	}