X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/427c0dda0c9fb207d8abdd92e3f77f91af9b682d..9b33de72cd2469bedac2b5f0a48a8782571ea9db:/src/LR0.c diff --git a/src/LR0.c b/src/LR0.c index 7dd7b441..945d41f8 100644 --- a/src/LR0.c +++ b/src/LR0.c @@ -1,7 +1,7 @@ -/* Generate the nondeterministic finite state machine for bison, +/* Generate the nondeterministic finite state machine for Bison. - Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002 Free Software - Foundation, Inc. + Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002, 2004, 2005, 2006 + Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -17,36 +17,39 @@ 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. */ /* See comments in state.h for the data structures that represent it. The entry point is generate_states. */ +#include <config.h> #include "system.h" -#include "bitset.h" -#include "quotearg.h" -#include "symtab.h" -#include "gram.h" + +#include <bitset.h> +#include <quotearg.h> + +#include "LR0.h" +#include "closure.h" +#include "complain.h" #include "getargs.h" -#include "reader.h" #include "gram.h" -#include "state.h" -#include "complain.h" -#include "closure.h" -#include "LR0.h" +#include "gram.h" #include "lalr.h" +#include "reader.h" #include "reduce.h" +#include "state.h" +#include "symtab.h" -typedef struct state_list_s +typedef struct state_list { - struct state_list_s *next; - state_t *state; -} state_list_t; + struct state_list *next; + state *state; +} state_list; -static state_list_t *first_state = NULL; -static state_list_t *last_state = NULL; +static state_list *first_state = NULL; +static state_list *last_state = NULL; /*------------------------------------------------------------------. @@ -54,24 +57,18 @@ static state_list_t *last_state = NULL; | later examination, in order to find its transitions. Return it. | `------------------------------------------------------------------*/ -static state_t * -state_list_append (symbol_number_t symbol, - size_t core_size, item_number_t *core) +static state * +state_list_append (symbol_number sym, size_t core_size, item_number *core) { - state_list_t *node = XMALLOC (state_list_t, 1); - state_t *state = state_new (symbol, core_size, core); + state_list *node = xmalloc (sizeof *node); + state *s = state_new (sym, core_size, core); if (trace_flag & trace_automaton) fprintf (stderr, "state_list_append (state = %d, symbol = %d (%s))\n", - nstates, symbol, symbols[symbol]->tag); - - /* If this is the endtoken, and this is not the initial state, then - this is the final state. */ - if (symbol == 0 && first_state) - final_state = state; + nstates, sym, symbols[sym]->tag); node->next = NULL; - node->state = state; + node->state = s; if (!first_state) first_state = node; @@ -79,33 +76,34 @@ state_list_append (symbol_number_t symbol, last_state->next = node; last_state = node; - return state; + return s; } static int nshifts; -static symbol_number_t *shift_symbol = NULL; +static symbol_number *shift_symbol; -static rule_t **redset = NULL; -static state_t **shiftset = NULL; +static rule **redset; +static state **shiftset; -static item_number_t **kernel_base = NULL; -static int *kernel_size = NULL; -static item_number_t *kernel_items = NULL; +static item_number **kernel_base; +static int *kernel_size; +static item_number *kernel_items; static void allocate_itemsets (void) { - symbol_number_t i; - rule_number_t r; - item_number_t *rhsp; + symbol_number i; + rule_number r; + item_number *rhsp; /* Count the number of occurrences of all the symbols in RITEMS. Note that useless productions (hence useless nonterminals) are browsed too, hence we need to allocate room for _all_ the symbols. */ - int count = 0; - short *symbol_count = XCALLOC (short, nsyms + nuseless_nonterminals); + size_t count = 0; + size_t *symbol_count = xcalloc (nsyms + nuseless_nonterminals, + sizeof *symbol_count); for (r = 0; r < nrules; ++r) for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp) @@ -116,13 +114,12 @@ allocate_itemsets (void) /* See comments before new_itemsets. All the vectors of items live inside KERNEL_ITEMS. The number of active items after - some symbol cannot be more than the number of times that symbol - appears as an item, which is SYMBOL_COUNT[SYMBOL]. + some symbol S cannot be more than the number of times that S + appears as an item, which is SYMBOL_COUNT[S]. We allocate that much space for each symbol. */ - kernel_base = XCALLOC (item_number_t *, nsyms); - if (count) - kernel_items = XCALLOC (item_number_t, count); + kernel_base = xnmalloc (nsyms, sizeof *kernel_base); + kernel_items = xnmalloc (count, sizeof *kernel_items); count = 0; for (i = 0; i < nsyms; i++) @@ -132,7 +129,7 @@ allocate_itemsets (void) } free (symbol_count); - kernel_size = XCALLOC (int, nsyms); + kernel_size = xnmalloc (nsyms, sizeof *kernel_size); } @@ -141,10 +138,10 @@ allocate_storage (void) { allocate_itemsets (); - shiftset = XCALLOC (state_t *, nsyms); - redset = XCALLOC (rule_t *, nrules); + shiftset = xnmalloc (nsyms, sizeof *shiftset); + redset = xnmalloc (nrules, sizeof *redset); state_hash_new (); - shift_symbol = XCALLOC (symbol_number_t, nsyms); + shift_symbol = xnmalloc (nsyms, sizeof *shift_symbol); } @@ -156,7 +153,7 @@ free_storage (void) free (shiftset); free (kernel_base); free (kernel_size); - XFREE (kernel_items); + free (kernel_items); state_hash_free (); } @@ -164,7 +161,7 @@ free_storage (void) /*---------------------------------------------------------------. -| Find which symbols can be shifted in STATE, and for each one | +| Find which symbols can be shifted in S, and for each one | | record which items would be active after that shift. Uses the | | contents of itemset. | | | @@ -175,99 +172,89 @@ free_storage (void) `---------------------------------------------------------------*/ static void -new_itemsets (state_t *state) +new_itemsets (state *s) { - int i; + size_t i; if (trace_flag & trace_automaton) - fprintf (stderr, "Entering new_itemsets, state = %d\n", - state->number); + fprintf (stderr, "Entering new_itemsets, state = %d\n", s->number); - for (i = 0; i < nsyms; i++) - kernel_size[i] = 0; + memset (kernel_size, 0, nsyms * sizeof *kernel_size); nshifts = 0; for (i = 0; i < nritemset; ++i) if (ritem[itemset[i]] >= 0) { - symbol_number_t symbol - = item_number_as_symbol_number (ritem[itemset[i]]); - if (!kernel_size[symbol]) + symbol_number sym = item_number_as_symbol_number (ritem[itemset[i]]); + if (!kernel_size[sym]) { - shift_symbol[nshifts] = symbol; + shift_symbol[nshifts] = sym; nshifts++; } - kernel_base[symbol][kernel_size[symbol]] = itemset[i] + 1; - kernel_size[symbol]++; + kernel_base[sym][kernel_size[sym]] = itemset[i] + 1; + kernel_size[sym]++; } } -/*-----------------------------------------------------------------. -| Find the state we would get to (from the current state) by | -| shifting SYMBOL. Create a new state if no equivalent one exists | -| already. Used by append_states. | -`-----------------------------------------------------------------*/ +/*--------------------------------------------------------------. +| Find the state we would get to (from the current state) by | +| shifting SYM. Create a new state if no equivalent one exists | +| already. Used by append_states. | +`--------------------------------------------------------------*/ -static state_t * -get_state (symbol_number_t symbol, size_t core_size, item_number_t *core) +static state * +get_state (symbol_number sym, size_t core_size, item_number *core) { - state_t *sp; + state *s; if (trace_flag & trace_automaton) fprintf (stderr, "Entering get_state, symbol = %d (%s)\n", - symbol, symbols[symbol]->tag); + sym, symbols[sym]->tag); - sp = state_hash_lookup (core_size, core); - if (!sp) - sp = state_list_append (symbol, core_size, core); + s = state_hash_lookup (core_size, core); + if (!s) + s = state_list_append (sym, core_size, core); if (trace_flag & trace_automaton) - fprintf (stderr, "Exiting get_state => %d\n", sp->number); + fprintf (stderr, "Exiting get_state => %d\n", s->number); - return sp; + return s; } /*---------------------------------------------------------------. | Use the information computed by new_itemsets to find the state | -| numbers reached by each shift transition from STATE. | +| numbers reached by each shift transition from S. | | | | SHIFTSET is set up as a vector of those states. | `---------------------------------------------------------------*/ static void -append_states (state_t *state) +append_states (state *s) { int i; - int j; - symbol_number_t symbol; if (trace_flag & trace_automaton) - fprintf (stderr, "Entering append_states, state = %d\n", - state->number); + fprintf (stderr, "Entering append_states, state = %d\n", s->number); - /* first sort shift_symbol into increasing order */ + /* First sort shift_symbol into increasing order. */ for (i = 1; i < nshifts; i++) { - symbol = shift_symbol[i]; - j = i; - while (j > 0 && shift_symbol[j - 1] > symbol) - { - shift_symbol[j] = shift_symbol[j - 1]; - j--; - } - shift_symbol[j] = symbol; + symbol_number sym = shift_symbol[i]; + int j; + for (j = i; 0 < j && sym < shift_symbol[j - 1]; j--) + shift_symbol[j] = shift_symbol[j - 1]; + shift_symbol[j] = sym; } for (i = 0; i < nshifts; i++) { - symbol = shift_symbol[i]; - shiftset[i] = get_state (symbol, - kernel_size[symbol], kernel_base[symbol]); + symbol_number sym = shift_symbol[i]; + shiftset[i] = get_state (sym, kernel_size[sym], kernel_base[sym]); } } @@ -279,21 +266,30 @@ append_states (state_t *state) `----------------------------------------------------------------*/ static void -save_reductions (state_t *state) +save_reductions (state *s) { int count = 0; - int i; + size_t i; /* Find and count the active items that represent ends of rules. */ for (i = 0; i < nritemset; ++i) { - int item = ritem[itemset[i]]; - if (item < 0) - redset[count++] = &rules[item_number_as_rule_number (item)]; + item_number item = ritem[itemset[i]]; + if (item_number_is_rule_number (item)) + { + rule_number r = item_number_as_rule_number (item); + redset[count++] = &rules[r]; + if (r == 0) + { + /* This is "reduce 0", i.e., accept. */ + aver (!final_state); + final_state = s; + } + } } /* Make a reductions structure and copy the data into it. */ - state_reductions_set (state, count, redset); + state_reductions_set (s, count, redset); } @@ -304,23 +300,23 @@ save_reductions (state_t *state) static void set_states (void) { - states = XCALLOC (state_t *, nstates); + states = xcalloc (nstates, sizeof *states); while (first_state) { - state_list_t *this = first_state; + state_list *this = first_state; /* Pessimization, but simplification of the code: make sure all the states have valid transitions and reductions members, even if reduced to 0. It is too soon for errs, which are computed later, but set_conflicts. */ - state_t *state = this->state; - if (!state->transitions) - state_transitions_set (state, 0, 0); - if (!state->reductions) - state_reductions_set (state, 0, 0); + state *s = this->state; + if (!s->transitions) + state_transitions_set (s, 0, 0); + if (!s->reductions) + state_reductions_set (s, 0, 0); - states[state->number] = state; + states[s->number] = s; first_state = this->next; free (this); @@ -338,44 +334,38 @@ set_states (void) void generate_states (void) { - state_list_t *list = NULL; + item_number initial_core = 0; + state_list *list = NULL; allocate_storage (); new_closure (nritems); /* Create the initial state. The 0 at the lhs is the index of the item of this initial rule. */ - kernel_base[0][0] = 0; - kernel_size[0] = 1; - state_list_append (0, kernel_size[0], kernel_base[0]); - - list = first_state; + state_list_append (0, 1, &initial_core); - while (list) + /* States are queued when they are created; process them all. */ + for (list = first_state; list; list = list->next) { - state_t *state = list->state; + state *s = list->state; if (trace_flag & trace_automaton) fprintf (stderr, "Processing state %d (reached by %s)\n", - state->number, - symbols[state->accessing_symbol]->tag); + s->number, + symbols[s->accessing_symbol]->tag); /* Set up ruleset and itemset for the transitions out of this state. ruleset gets a 1 bit for each rule that could reduce now. itemset gets a vector of all the items that could be accepted next. */ - closure (state->items, state->nitems); + closure (s->items, s->nitems); /* Record the reductions allowed out of this state. */ - save_reductions (state); + save_reductions (s); /* Find the itemsets of the states that shifts can reach. */ - new_itemsets (state); + new_itemsets (s); /* Find or create the core structures for those states. */ - append_states (state); + append_states (s); /* Create the shifts structures for the shifts to those states, now that the state numbers transitioning to are known. */ - state_transitions_set (state, nshifts, shiftset); - - /* States are queued when they are created; process them all. - */ - list = list->next; + state_transitions_set (s, nshifts, shiftset); } /* discard various storage */