X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/5e893e1c884b0d39965d6b694821a36648f1eda1..03b9e27342b94ef7a83bff78259fd8415f00584a:/src/state.c diff --git a/src/state.c b/src/state.c index 7c3b6921..3afe46cf 100644 --- a/src/state.c +++ b/src/state.c @@ -1,5 +1,6 @@ -/* Type definitions for nondeterministic finite state machine for bison, - Copyright 2001 Free Software Foundation, Inc. +/* Type definitions for nondeterministic finite state machine for Bison. + + Copyright (C) 2001, 2002 Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -20,16 +21,350 @@ #include "system.h" + +#include + +#include "complain.h" +#include "gram.h" #include "state.h" + + /*-------------------. + | Shifts and Gotos. | + `-------------------*/ + + +/*-----------------------------------------. +| Create a new array of NUM shifts/gotos. | +`-----------------------------------------*/ + +static transitions * +transitions_new (int num, state **the_states) +{ + size_t states_size = num * sizeof *the_states; + transitions *res = xmalloc (offsetof (transitions, states) + states_size); + res->num = num; + memcpy (res->states, the_states, states_size); + return res; +} + + +/*-------------------------------------------------------------------. +| Return the state such these TRANSITIONS contain a shift/goto to it | +| on S. Abort if none found. | +`-------------------------------------------------------------------*/ + +state * +transitions_to (transitions *shifts, symbol_number s) +{ + int j; + for (j = 0; j < shifts->num; j++) + if (TRANSITION_SYMBOL (shifts, j) == s) + return shifts->states[j]; + abort (); +} + + + /*--------------------. + | Error transitions. | + `--------------------*/ + + /*---------------------------------. -| Create a new array of N shitfs. | +| Create a new array of NUM errs. | `---------------------------------*/ -shifts * -shifts_new (int n) +errs * +errs_new (int num, symbol **tokens) { - shifts *res = SHIFTS_ALLOC (n); - res->nshifts = n; + size_t symbols_size = num * sizeof *tokens; + errs *res = xmalloc (offsetof (errs, symbols) + symbols_size); + res->num = num; + memcpy (res->symbols, tokens, symbols_size); return res; } + + + + + /*-------------. + | Reductions. | + `-------------*/ + + +/*---------------------------------------. +| Create a new array of NUM reductions. | +`---------------------------------------*/ + +static reductions * +reductions_new (int num, rule **reds) +{ + size_t rules_size = num * sizeof *reds; + reductions *res = xmalloc (offsetof (reductions, rules) + rules_size); + res->num = num; + res->lookaheads = NULL; + memcpy (res->rules, reds, rules_size); + return res; +} + + + + /*---------. + | States. | + `---------*/ + + +state_number nstates = 0; +/* FINAL_STATE is properly set by new_state when it recognizes its + accessing symbol: $end. */ +state *final_state = NULL; + + +/*------------------------------------------------------------------. +| Create a new state with ACCESSING_SYMBOL, for those items. Store | +| it in the state hash table. | +`------------------------------------------------------------------*/ + +state * +state_new (symbol_number accessing_symbol, + size_t nitems, item_number *core) +{ + state *res; + size_t items_size = nitems * sizeof *core; + + if (STATE_NUMBER_MAXIMUM <= nstates) + abort (); + + res = xmalloc (offsetof (state, items) + items_size); + res->number = nstates++; + res->accessing_symbol = accessing_symbol; + res->transitions = NULL; + res->reductions = NULL; + res->errs = NULL; + res->consistent = 0; + res->solved_conflicts = NULL; + + res->nitems = nitems; + memcpy (res->items, core, items_size); + + state_hash_insert (res); + + return res; +} + + +/*---------. +| Free S. | +`---------*/ + +static void +state_free (state *s) +{ + free (s->transitions); + free (s->reductions); + free (s->errs); + free (s); +} + + +/*---------------------------. +| Set the transitions of S. | +`---------------------------*/ + +void +state_transitions_set (state *s, int num, state **trans) +{ + if (s->transitions) + abort (); + s->transitions = transitions_new (num, trans); +} + + +/*--------------------------. +| Set the reductions of S. | +`--------------------------*/ + +void +state_reductions_set (state *s, int num, rule **reds) +{ + if (s->reductions) + abort (); + s->reductions = reductions_new (num, reds); +} + + +int +state_reduction_find (state *s, rule *r) +{ + int i; + reductions *reds = s->reductions; + for (i = 0; i < reds->num; ++i) + if (reds->rules[i] == r) + return i; + return -1; +} + + +/*--------------------. +| Set the errs of S. | +`--------------------*/ + +void +state_errs_set (state *s, int num, symbol **tokens) +{ + if (s->errs) + abort (); + s->errs = errs_new (num, tokens); +} + + + +/*-----------------------------------------------------. +| Print on OUT all the lookaheads such that S wants to | +| reduce R. | +`-----------------------------------------------------*/ + +void +state_rule_lookaheads_print (state *s, rule *r, FILE *out) +{ + /* Find the reduction we are handling. */ + reductions *reds = s->reductions; + int red = state_reduction_find (s, r); + + /* Print them if there are. */ + if (reds->lookaheads && red != -1) + { + bitset_iterator biter; + int k; + int not_first = 0; + fprintf (out, " ["); + BITSET_FOR_EACH (biter, reds->lookaheads[red], k, 0) + fprintf (out, "%s%s", + not_first++ ? ", " : "", + symbols[k]->tag); + fprintf (out, "]"); + } +} + + +/*----------------------. +| A state hash table. | +`----------------------*/ + +/* Initial capacity of states hash table. */ +#define HT_INITIAL_CAPACITY 257 + +static struct hash_table *state_table = NULL; + +/* Two states are equal if they have the same core items. */ +static inline bool +state_compare (state const *s1, state const *s2) +{ + int i; + + if (s1->nitems != s2->nitems) + return false; + + for (i = 0; i < s1->nitems; ++i) + if (s1->items[i] != s2->items[i]) + return false; + + return true; +} + +static bool +state_comparator (void const *s1, void const *s2) +{ + return state_compare (s1, s2); +} + +static inline unsigned int +state_hash (state const *s, unsigned int tablesize) +{ + /* Add up the state's item numbers to get a hash key. */ + unsigned int key = 0; + int i; + for (i = 0; i < s->nitems; ++i) + key += s->items[i]; + return key % tablesize; +} + +static unsigned int +state_hasher (void const *s, unsigned int tablesize) +{ + return state_hash (s, tablesize); +} + + +/*-------------------------------. +| Create the states hash table. | +`-------------------------------*/ + +void +state_hash_new (void) +{ + state_table = hash_initialize (HT_INITIAL_CAPACITY, + NULL, + state_hasher, + state_comparator, + NULL); +} + + +/*---------------------------------------------. +| Free the states hash table, not the states. | +`---------------------------------------------*/ + +void +state_hash_free (void) +{ + hash_free (state_table); +} + + +/*-----------------------------------. +| Insert S in the state hash table. | +`-----------------------------------*/ + +void +state_hash_insert (state *s) +{ + hash_insert (state_table, s); +} + + +/*------------------------------------------------------------------. +| Find the state associated to the CORE, and return it. If it does | +| not exist yet, return NULL. | +`------------------------------------------------------------------*/ + +state * +state_hash_lookup (size_t nitems, item_number *core) +{ + size_t items_size = nitems * sizeof *core; + state *probe = xmalloc (offsetof (state, items) + items_size); + state *entry; + + probe->nitems = nitems; + memcpy (probe->items, core, items_size); + entry = hash_lookup (state_table, probe); + free (probe); + return entry; +} + +/* All the decorated states, indexed by the state number. */ +state **states = NULL; + + +/*----------------------. +| Free all the states. | +`----------------------*/ + +void +states_free (void) +{ + state_number i; + for (i = 0; i < nstates; ++i) + state_free (states[i]); + free (states); +}