-/* Type definitions for nondeterministic finite state machine for bison,
- Copyright 1984, 1989, 2000, 2001 Free Software Foundation, Inc.
+/* Type definitions for nondeterministic finite state machine for Bison.
+
+ Copyright (C) 1984, 1989, 2000, 2001, 2002, 2003, 2004, 2007 Free
+ Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
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
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 transitions are shifts (push the lookahead token
- and read another) 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 lookahead token alone). When the states are
- generated, these transitions are represented in two other lists.
+ 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
+ lookahead token alone). When the states are generated, these
+ actions are represented in two other lists.
- Each shifts structure describes the possible shift transitions out
- of one state, the state whose number is in the number field. The
- shifts structures are linked through next and first_shift points to
- them. Each contains a vector of numbers of the states that shift
- transitions can go to. The accessing_symbol fields of those
- states' cores say what kind of input leads to them.
+ Each transition structure describes the possible transitions out
+ of one state, the state whose number is in the number field. Each
+ contains a vector of numbers of the states that transitions can go
+ to. The accessing_symbol fields of those states' cores say what
+ kind of input leads to them.
- A shift to state zero should be ignored. Conflict resolution
- deletes shifts by changing them to zero.
+ A transition to state zero should be ignored: conflict resolution
+ 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).
For each state, the tokens that are errors for this reason are
- recorded in an errs structure, which has the state number in its
- number field. The rest of the errs structure is full of token
- numbers.
+ recorded in an errs structure, which holds the token numbers.
- There is at least one shift transition present in state zero. It
+ There is at least one goto transition present in state zero. It
leads to a next-to-final state whose accessing_symbol is the
grammar's start symbol. The next-to-final state has one shift to
the final state, whose accessing_symbol is zero (end of input).
- The final state has one shift, which goes to the termination state
- (whose number is nstates-1). The reason for the extra state at the
- end is to placate the parser's strategy of making all decisions one
- token ahead of its actions. */
+ The final state has one shift, which goes to the termination state.
+ The reason for the extra state at the end is to placate the
+ parser's strategy of making all decisions one token ahead of its
+ actions. */
#ifndef STATE_H_
# define STATE_H_
-# include "bitsetv.h"
+# include <bitset.h>
+
+# include "gram.h"
+# include "symtab.h"
/*-------------------.
| Numbering states. |
`-------------------*/
-typedef short state_number_t;
-# define STATE_NUMBER_MAX ((state_number_t) SHRT_MAX)
+typedef int state_number;
+# define STATE_NUMBER_MAXIMUM INT_MAX
+
+/* Be ready to map a state_number to an int. */
+static inline int
+state_number_as_int (state_number s)
+{
+ return s;
+}
+
-/* Be ready to map a state_number_t to an int. */
-# define state_number_as_int(Tok) ((int) (Tok))
+typedef struct state state;
/*--------------.
| Transitions. |
`--------------*/
-typedef struct transtion_s
+typedef struct
{
- short num;
- state_number_t states[1];
-} transitions_t;
+ int num;
+ state *states[1];
+} transitions;
-/* What is the symbol which is shifted by TRANSITIONS->states[Shift]? Can
- be a token (amongst which the error token), or non terminals in
- case of gotos. */
+/* What is the symbol labelling the transition to
+ TRANSITIONS->states[Num]? Can be a token (amongst which the error
+ token), or non terminals in case of gotos. */
-#define TRANSITION_SYMBOL(Transitions, Shift) \
- (states[Transitions->states[Shift]]->accessing_symbol)
+#define TRANSITION_SYMBOL(Transitions, Num) \
+ (Transitions->states[Num]->accessing_symbol)
-/* Is the TRANSITIONS->states[Shift] a real shift? (as opposed to gotos.) */
+/* Is the TRANSITIONS->states[Num] a shift? (as opposed to gotos). */
-#define TRANSITION_IS_SHIFT(Transitions, Shift) \
- (ISTOKEN (TRANSITION_SYMBOL (Transitions, Shift)))
+#define TRANSITION_IS_SHIFT(Transitions, Num) \
+ (ISTOKEN (TRANSITION_SYMBOL (Transitions, Num)))
-/* Is the TRANSITIONS->states[Shift] a goto?. */
+/* Is the TRANSITIONS->states[Num] a goto?. */
-#define TRANSITION_IS_GOTO(Transitions, Shift) \
- (!TRANSITION_IS_SHIFT (Transitions, Shift))
+#define TRANSITION_IS_GOTO(Transitions, Num) \
+ (!TRANSITION_IS_SHIFT (Transitions, Num))
-/* Is the TRANSITIONS->states[Shift] then handling of the error token?. */
+/* Is the TRANSITIONS->states[Num] labelled by the error token? */
-#define TRANSITION_IS_ERROR(Transitions, Shift) \
- (TRANSITION_SYMBOL (Transitions, Shift) == errtoken->number)
+#define TRANSITION_IS_ERROR(Transitions, Num) \
+ (TRANSITION_SYMBOL (Transitions, Num) == errtoken->number)
/* When resolving a SR conflicts, if the reduction wins, the shift is
disabled. */
-#define TRANSITION_DISABLE(Transitions, Shift) \
- (Transitions->states[Shift] = 0)
+#define TRANSITION_DISABLE(Transitions, Num) \
+ (Transitions->states[Num] = NULL)
+
+#define TRANSITION_IS_DISABLED(Transitions, Num) \
+ (Transitions->states[Num] == NULL)
+
+
+/* Iterate over each transition over a token (shifts). */
+#define FOR_EACH_SHIFT(Transitions, Iter) \
+ for (Iter = 0; \
+ Iter < Transitions->num \
+ && (TRANSITION_IS_DISABLED (Transitions, Iter) \
+ || TRANSITION_IS_SHIFT (Transitions, Iter)); \
+ ++Iter) \
+ if (!TRANSITION_IS_DISABLED (Transitions, Iter))
-#define TRANSITION_IS_DISABLED(Transitions, Shift) \
- (Transitions->states[Shift] == 0)
-/* Return the state such these TRANSITIONS contain a shift/goto to it on
- SYMBOL. Aborts if none found. */
-struct state_s;
-struct state_s *transitions_to PARAMS ((transitions_t *state,
- symbol_number_t s));
+/* Return the state such SHIFTS contain a shift/goto to it on SYM.
+ Abort if none found. */
+struct state *transitions_to (transitions *shifts, symbol_number sym);
/*-------.
| Errs. |
`-------*/
-typedef struct errs_s
+typedef struct
{
- short num;
- symbol_number_t symbols[1];
-} errs_t;
+ int num;
+ symbol *symbols[1];
+} errs;
-errs_t *errs_new PARAMS ((int n));
-errs_t *errs_dup PARAMS ((errs_t *src));
+errs *errs_new (int num, symbol **tokens);
/*-------------.
| Reductions. |
`-------------*/
-typedef struct reductions_s
+typedef struct
{
- short num;
- rule_number_t rules[1];
-} reductions_t;
+ int num;
+ bitset *lookahead_tokens;
+ rule *rules[1];
+} reductions;
-/*----------.
-| State_t. |
-`----------*/
+/*---------.
+| states. |
+`---------*/
-typedef struct state_s
+struct state
{
- state_number_t number;
- symbol_number_t accessing_symbol;
- transitions_t *shifts;
- reductions_t *reductions;
- errs_t *errs;
+ state_number number;
+ symbol_number accessing_symbol;
+ transitions *transitions;
+ reductions *reductions;
+ errs *errs;
/* Nonzero if no lookahead is needed to decide what to do in state S. */
char consistent;
- /* Used in LALR, not LR(0).
-
- When a state is not consistent (there is an S/R or R/R conflict),
- lookaheads are needed to enable the reductions. NLOOKAHEADS is
- the number of lookahead guarded reductions of the
- LOOKAHEADS_RULE. For each rule LOOKAHEADS_RULE[R], LOOKAHEADS[R]
- is the bitset of the lookaheads enabling this reduction. */
- int nlookaheads;
- bitsetv lookaheads;
- rule_t **lookaheads_rule;
-
/* If some conflicts were solved thanks to precedence/associativity,
a human readable description of the resolution. */
const char *solved_conflicts;
+ /* Conflict resolution sometimes makes states unreachable. Initialized to 0
+ in state_new and then used by state_remove_unreachable_states after
+ conflicts_solve. */
+ bool reachable;
+
/* Its items. Must be last, since ITEMS can be arbitrarily large.
*/
- unsigned short nitems;
- item_number_t items[1];
-} state_t;
+ size_t nitems;
+ item_number items[1];
+};
-extern state_number_t nstates;
-extern state_t *final_state;
+extern state_number nstates;
+extern state *final_state;
/* Create a new state with ACCESSING_SYMBOL for those items. */
-state_t *state_new PARAMS ((symbol_number_t accessing_symbol,
- size_t core_size, item_number_t *core));
+state *state_new (symbol_number accessing_symbol,
+ size_t core_size, item_number *core);
-/* Set the shifts of STATE. */
-void state_transitions_set PARAMS ((state_t *state,
- int nshifts, state_number_t *shifts));
+/* Set the transitions of STATE. */
+void state_transitions_set (state *s, int num, state **trans);
/* Set the reductions of STATE. */
-void state_reductions_set PARAMS ((state_t *state,
- int nreductions, short *reductions));
+void state_reductions_set (state *s, int num, rule **reds);
+
+int state_reduction_find (state *s, rule *r);
-/* Print on OUT all the lookaheads such that this STATE wants to
- reduce this RULE. */
-void state_rule_lookaheads_print PARAMS ((state_t *state, rule_t *rule,
- FILE *out));
+/* Set the errs of STATE. */
+void state_errs_set (state *s, int num, symbol **errors);
+
+/* Print on OUT all the lookahead tokens such that this STATE wants to
+ reduce R. */
+void state_rule_lookahead_tokens_print (state *s, rule *r, FILE *out);
/* Create/destroy the states hash table. */
-void state_hash_new PARAMS ((void));
-void state_hash_free PARAMS ((void));
+void state_hash_new (void);
+void state_hash_free (void);
/* Find the state associated to the CORE, and return it. If it does
not exist yet, return NULL. */
-state_t *state_hash_lookup PARAMS ((size_t core_size, item_number_t *core));
+state *state_hash_lookup (size_t core_size, item_number *core);
/* Insert STATE in the state hash table. */
-void state_hash_insert PARAMS ((state_t *state));
+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_t **states;
+extern state **states;
/* Free all the states. */
-void states_free PARAMS ((void));
+void states_free (void);
+
#endif /* !STATE_H_ */
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