X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/32e1e0a4865d64946a5497aff057d7be28c1cc3d..e2a8c0f591c1f8ca0909faee23914f62bacb866c:/src/LR0.c diff --git a/src/LR0.c b/src/LR0.c index 27282bd1..259b8912 100644 --- a/src/LR0.c +++ b/src/LR0.c @@ -1,5 +1,7 @@ -/* Generate the nondeterministic finite state machine for bison, - Copyright 1984, 1986, 1989, 2000, 2001, 2002 Free Software Foundation, Inc. +/* Generate the nondeterministic finite state machine for Bison. + + Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002, 2004, 2005 Free + Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -15,76 +17,95 @@ 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 #include "system.h" -#include "bitset.h" -#include "quotearg.h" -#include "symtab.h" -#include "gram.h" + +#include +#include + +#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; -static void -state_list_append (state_t *state) + +/*------------------------------------------------------------------. +| A state was just discovered from another state. Queue it for | +| later examination, in order to find its transitions. Return it. | +`------------------------------------------------------------------*/ + +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_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, sym, symbols[sym]->tag); + node->next = NULL; - node->state = state; + node->state = s; if (!first_state) first_state = node; if (last_state) last_state->next = node; last_state = node; + + return s; } static int nshifts; -static symbol_number_t *shift_symbol = NULL; +static symbol_number *shift_symbol; -static short *redset = NULL; -static state_number_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) { - int i, 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 = 1; r < nrules + 1; ++r) + for (r = 0; r < nrules; ++r) for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp) { count++; @@ -93,13 +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++) @@ -109,7 +129,7 @@ allocate_itemsets (void) } free (symbol_count); - kernel_size = XCALLOC (int, nsyms); + kernel_size = xnmalloc (nsyms, sizeof *kernel_size); } @@ -118,10 +138,10 @@ allocate_storage (void) { allocate_itemsets (); - shiftset = XCALLOC (state_number_t, nsyms); - redset = XCALLOC (short, nrules + 1); + 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); } @@ -133,7 +153,7 @@ free_storage (void) free (shiftset); free (kernel_base); free (kernel_size); - XFREE (kernel_items); + free (kernel_items); state_hash_free (); } @@ -141,7 +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. | | | @@ -152,141 +172,93 @@ free_storage (void) `---------------------------------------------------------------*/ static void -new_itemsets (state_t *state) +new_itemsets (state *s) { - int i; + size_t i; - if (trace_flag) - fprintf (stderr, "Entering new_itemsets, state = %d\n", - state->number); + if (trace_flag & trace_automaton) + 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]++; } } -/*-----------------------------------------------------------------. -| Subroutine of get_state. Create a new state for those items, if | -| necessary. | -`-----------------------------------------------------------------*/ - -static state_t * -new_state (symbol_number_t symbol, size_t core_size, item_number_t *core) -{ - state_t *res; - - if (trace_flag) - fprintf (stderr, "Entering new_state, state = %d, symbol = %d (%s)\n", - nstates, symbol, symbol_tag_get (symbols[symbol])); - - res = state_new (symbol, core_size, core); - state_hash_insert (res); - - /* If this is the eoftoken, and this is not the initial state, then - this is the final state. */ - if (symbol == 0 && first_state) - final_state = res; - - state_list_append (res); - return res; -} - - /*--------------------------------------------------------------. -| Find the state number for 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_number_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) + if (trace_flag & trace_automaton) fprintf (stderr, "Entering get_state, symbol = %d (%s)\n", - symbol, symbol_tag_get (symbols[symbol])); + sym, symbols[sym]->tag); - sp = state_hash_lookup (core_size, core); - if (!sp) - sp = new_state (symbol, core_size, core); + s = state_hash_lookup (core_size, core); + if (!s) + s = state_list_append (sym, core_size, core); - if (trace_flag) - fprintf (stderr, "Exiting get_state => %d\n", sp->number); + if (trace_flag & trace_automaton) + fprintf (stderr, "Exiting get_state => %d\n", s->number); - return sp->number; + return s; } -/*------------------------------------------------------------------. -| Use the information computed by new_itemsets to find the state | -| numbers reached by each shift transition from STATE. | -| | -| SHIFTSET is set up as a vector of state numbers of those states. | -`------------------------------------------------------------------*/ +/*---------------------------------------------------------------. +| Use the information computed by new_itemsets to find the 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) - fprintf (stderr, "Entering append_states, state = %d\n", - state->number); + if (trace_flag & trace_automaton) + 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]); } } -static void -new_states (void) -{ - /* 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 (new_state (0, kernel_size[0], kernel_base[0])); -} - - - /*----------------------------------------------------------------. | Find which rules can be used for reduction transitions from the | | current state and make a reductions structure for the state to | @@ -294,27 +266,30 @@ new_states (void) `----------------------------------------------------------------*/ static void -save_reductions (state_t *state) +save_reductions (state *s) { int count = 0; - int i; - - /* If this is the final state, we want it to have no reductions at - all, although it has one for `START_SYMBOL EOF .'. */ - if (final_state && state->number == final_state->number) - return; + 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++] = -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. */ + assert (!final_state); + final_state = s; + } + } } /* Make a reductions structure and copy the data into it. */ - state->reductions = reductions_new (count); - memcpy (state->reductions->rules, redset, count * sizeof (redset[0])); + state_reductions_set (s, count, redset); } @@ -325,24 +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 a shifts, errs, and reductions, even if - reduced to 0. */ - state_t *state = this->state; - if (!state->shifts) - state_shifts_set (state, 0, 0); - if (!state->errs) - state->errs = errs_new (0); - if (!state->reductions) - state->reductions = reductions_new (0); - - states[state->number] = state; + 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 *s = this->state; + if (!s->transitions) + state_transitions_set (s, 0, 0); + if (!s->reductions) + state_reductions_set (s, 0, 0); + + states[s->number] = s; first_state = this->next; free (this); @@ -360,38 +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); - new_states (); - list = first_state; - while (list) + /* Create the initial state. The 0 at the lhs is the index of the + item of this initial rule. */ + state_list_append (0, 1, &initial_core); + + /* States are queued when they are created; process them all. */ + for (list = first_state; list; list = list->next) { - state_t *state = list->state; - if (trace_flag) + state *s = list->state; + if (trace_flag & trace_automaton) fprintf (stderr, "Processing state %d (reached by %s)\n", - state->number, - symbol_tag_get (symbols[state->accessing_symbol])); + 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_shifts_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 */