X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/f6fbd3da9d1366ccaa0163c6c93dde11e5720262..eb1b07409f0ccad9970c8a60ded9f2a56d205b9c:/src/state.h diff --git a/src/state.h b/src/state.h index 36395d16..390ab8af 100644 --- a/src/state.h +++ b/src/state.h @@ -1,6 +1,6 @@ /* Type definitions for nondeterministic finite state machine for Bison. - Copyright (C) 1984, 1989, 2000, 2001, 2002, 2003, 2004 Free + Copyright (C) 1984, 1989, 2000, 2001, 2002, 2003, 2004, 2007 Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -17,8 +17,8 @@ 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. */ + the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, + Boston, MA 02110-1301, USA. */ /* These type definitions are used to represent a nondeterministic @@ -44,13 +44,13 @@ ACCESSING_SYMBOL of the core. Each core contains a vector of NITEMS items which are the indices - in the RITEMS vector of the items that are selected in this state. + in the RITEM vector of the items that are selected in this state. - The two types of actions are shifts/gotos (push the look-ahead token + The two types of actions are shifts/gotos (push the lookahead token and read another/goto to the state designated by a nterm) and reductions (combine the last n things on the stack via a rule, replace them with the symbol that the rule derives, and leave the - look-ahead token alone). When the states are generated, these + lookahead token alone). When the states are generated, these actions are represented in two other lists. Each transition structure describes the possible transitions out @@ -63,9 +63,8 @@ deletes transitions by having them point to zero. Each reductions structure describes the possible reductions at the - state whose number is in the number field. The data is a list of - nreds rules, represented by their rule numbers. first_reduction - points to the list of these structures. + state whose number is in the number field. rules is an array of + num rules. lookahead_tokens is an array of bitsets, one per rule. Conflict resolution can decide that certain tokens in certain states should explicitly be errors (for implementing %nonassoc). @@ -185,7 +184,8 @@ errs *errs_new (int num, symbol **tokens); typedef struct { int num; - bitset *look_ahead_tokens; + bitset *lookahead_tokens; + /* Sorted ascendingly on rule number. */ rule *rules[1]; } reductions; @@ -203,15 +203,16 @@ struct state reductions *reductions; errs *errs; - /* Nonzero if no look-ahead is needed to decide what to do in state S. */ + /* If non-zero, then no lookahead sets on reduce actions are needed to + decide what to do in state S. */ char consistent; /* If some conflicts were solved thanks to precedence/associativity, a human readable description of the resolution. */ const char *solved_conflicts; - /* Its items. Must be last, since ITEMS can be arbitrarily large. - */ + /* Its items. Must be last, since ITEMS can be arbitrarily large. Sorted + ascendingly on item index in RITEM, which is sorted on rule number. */ size_t nitems; item_number items[1]; }; @@ -234,9 +235,9 @@ int state_reduction_find (state *s, rule *r); /* Set the errs of STATE. */ void state_errs_set (state *s, int num, symbol **errors); -/* Print on OUT all the look-ahead tokens such that this STATE wants to +/* Print on OUT all the lookahead tokens such that this STATE wants to reduce R. */ -void state_rule_look_ahead_tokens_print (state *s, rule *r, FILE *out); +void state_rule_lookahead_tokens_print (state *s, rule *r, FILE *out); /* Create/destroy the states hash table. */ void state_hash_new (void); @@ -249,9 +250,16 @@ state *state_hash_lookup (size_t core_size, item_number *core); /* Insert STATE in the state hash table. */ void state_hash_insert (state *s); +/* Remove unreachable states, renumber remaining states, update NSTATES, and + write to OLD_TO_NEW a mapping of old state numbers to new state numbers such + that the old value of NSTATES is written as the new state number for removed + states. The size of OLD_TO_NEW must be the old value of NSTATES. */ +void state_remove_unreachable_states (state_number old_to_new[]); + /* All the states, indexed by the state number. */ extern state **states; /* Free all the states. */ void states_free (void); + #endif /* !STATE_H_ */