X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/e68e0410aba6a9b976a1e496aa80ffb3d2095fb9..041308d0c03783c51ef362f888c957cd2a0e129a:/src/lalr.h diff --git a/src/lalr.h b/src/lalr.h index 696bc98d..75e957ec 100644 --- a/src/lalr.h +++ b/src/lalr.h @@ -1,77 +1,106 @@ -/* Compute look-ahead criteria for bison, - Copyright (C) 1984, 1986, 1989, 2000, 2002 Free Software Foundation, Inc. +/* Compute lookahead criteria for bison, + + Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006-2007, + 2009-2012 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 + This program 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. + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. - Bison is distributed in the hope that it will be useful, + This program 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. */ + along with this program. If not, see . */ #ifndef LALR_H_ # define LALR_H_ -#include "bitset.h" -#include "bitsetv.h" +# include +# include + +/* Import the definition of RULE_T. */ +# include "gram.h" /* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */ # include "state.h" -/* Import the definition of RULE_T. */ -# include "gram.h" -/* Compute how to make the finite state machine deterministic; find - which rules need lookahead in each state, and which lookahead - tokens they accept. */ +/** Build the LALR(1) automaton. + + Find which rules need lookahead in each state, and which lookahead + tokens they accept. -void lalr PARAMS ((void)); + Also builds: + - #goto_map + - #from_state + - #to_state + - #goto_follows +*/ +void lalr (void); +/** + * Set #nLA and allocate all reduction lookahead sets. Normally invoked by + * #lalr. + */ +void initialize_LA (void); -/* lalr() builds these data structures. */ +/** + * Build only: + * - #goto_map + * - #from_state + * - #to_state + * Normally invoked by #lalr. + */ +void set_goto_map (void); -/* GOTO_MAP, FROM_STATE and TO_STATE -- record each shift transition - which accepts a variable (a nonterminal). +/** + * Update state numbers recorded in #goto_map, #from_state, and #to_state such + * that: + * - \c nstates_old is the old number of states. + * - Where \c i is the old state number, old_to_new[i] is either: + * - \c nstates_old if state \c i is removed because it is unreachable. + * Thus, remove all goto entries involving this state. + * - The new state number. + */ +void lalr_update_state_numbers (state_number old_to_new[], + state_number nstates_old); - FROM_STATE[T] -- state number which a transition leads from. - TO_STATE[T] -- state number it leads to. + +/** Release the information related to lookahead tokens. + + Can be performed once the action tables are computed. */ +void lalr_free (void); + +typedef size_t goto_number; +# define GOTO_NUMBER_MAXIMUM ((goto_number) -1) + +/** Index into #from_state and #to_state. All the transitions that accept a particular variable are grouped together and GOTO_MAP[I - NTOKENS] is the index in FROM_STATE and TO_STATE of the first of them. */ +extern goto_number *goto_map; -typedef short goto_number_t; -# define GOTO_NUMBER_MAX ((goto_number_t) INT_MAX) - -extern goto_number_t *goto_map; -extern state_number_t *from_state; -extern state_number_t *to_state; - -/* LARULE is a vector which records the rules that need lookahead in - various states. The elements of LARULE that apply to state S are - those from LOOKAHEADS[S] through LOOKAHEADS[S+1]-1. +/** The size of #from_state and #to_state. */ +extern goto_number ngotos; - If LR is the length of LArule, then a number from 0 to LR-1 can - specify both a rule and a state where the rule might be applied. - */ +/** State number which a transition leads from. */ +extern state_number *from_state; -extern rule_t **LArule; +/** State number it leads to. */ +extern state_number *to_state; -/* LA is a LR by NTOKENS matrix of bits. LA[l, i] is 1 if the rule - LAruleno[l] is applicable in the appropriate state when the next - token is symbol i. If LA[l, i] and LA[l, j] are both 1 for i != j, - it is a conflict. */ +/** Map a state/symbol pair into its numeric representation. */ +goto_number map_goto (state_number s0, symbol_number sym); -extern bitsetv LA; +/* goto_follows[i] is the set of tokens following goto i. */ +extern bitsetv goto_follows; #endif /* !LALR_H_ */