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Unified Diff: bison/src/bison/2.4.1/bison-2.4.1-src/src/LR0.c

Issue 10807020: Add native Windows binary for bison. (Closed) Base URL: svn://chrome-svn/chrome/trunk/deps/third_party/
Patch Set: Created 8 years, 5 months ago
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Index: bison/src/bison/2.4.1/bison-2.4.1-src/src/LR0.c
===================================================================
--- bison/src/bison/2.4.1/bison-2.4.1-src/src/LR0.c (revision 0)
+++ bison/src/bison/2.4.1/bison-2.4.1-src/src/LR0.c (revision 0)
@@ -0,0 +1,377 @@
+/* Generate the nondeterministic finite state machine for Bison.
+
+ Copyright (C) 1984, 1986, 1989, 2000, 2001, 2002, 2004, 2005, 2006, 2007
+ Free Software Foundation, Inc.
+
+ This file is part of Bison, the GNU Compiler Compiler.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+
+/* 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 "LR0.h"
+#include "closure.h"
+#include "complain.h"
+#include "getargs.h"
+#include "gram.h"
+#include "gram.h"
+#include "lalr.h"
+#include "reader.h"
+#include "reduce.h"
+#include "state.h"
+#include "symtab.h"
+
+typedef struct state_list
+{
+ struct state_list *next;
+ state *state;
+} state_list;
+
+static state_list *first_state = NULL;
+static state_list *last_state = NULL;
+
+
+/*------------------------------------------------------------------.
+| 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 *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 = 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 *shift_symbol;
+
+static rule **redset;
+static state **shiftset;
+
+static item_number **kernel_base;
+static int *kernel_size;
+static item_number *kernel_items;
+
+
+static void
+allocate_itemsets (void)
+{
+ 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. */
+ 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)
+ {
+ count++;
+ symbol_count[*rhsp]++;
+ }
+
+ /* See comments before new_itemsets. All the vectors of items
+ live inside KERNEL_ITEMS. The number of active items after
+ 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 = xnmalloc (nsyms, sizeof *kernel_base);
+ kernel_items = xnmalloc (count, sizeof *kernel_items);
+
+ count = 0;
+ for (i = 0; i < nsyms; i++)
+ {
+ kernel_base[i] = kernel_items + count;
+ count += symbol_count[i];
+ }
+
+ free (symbol_count);
+ kernel_size = xnmalloc (nsyms, sizeof *kernel_size);
+}
+
+
+static void
+allocate_storage (void)
+{
+ allocate_itemsets ();
+
+ shiftset = xnmalloc (nsyms, sizeof *shiftset);
+ redset = xnmalloc (nrules, sizeof *redset);
+ state_hash_new ();
+ shift_symbol = xnmalloc (nsyms, sizeof *shift_symbol);
+}
+
+
+static void
+free_storage (void)
+{
+ free (shift_symbol);
+ free (redset);
+ free (shiftset);
+ free (kernel_base);
+ free (kernel_size);
+ free (kernel_items);
+ state_hash_free ();
+}
+
+
+
+
+/*---------------------------------------------------------------.
+| 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. |
+| |
+| shift_symbol is set to a vector of the symbols that can be |
+| shifted. For each symbol in the grammar, kernel_base[symbol] |
+| points to a vector of item numbers activated if that symbol is |
+| shifted, and kernel_size[symbol] is their numbers. |
+| |
+| itemset is sorted on item index in ritem, which is sorted on |
+| rule number. Compute each kernel_base[symbol] with the same |
+| sort. |
+`---------------------------------------------------------------*/
+
+static void
+new_itemsets (state *s)
+{
+ size_t i;
+
+ if (trace_flag & trace_automaton)
+ fprintf (stderr, "Entering new_itemsets, state = %d\n", s->number);
+
+ memset (kernel_size, 0, nsyms * sizeof *kernel_size);
+
+ nshifts = 0;
+
+ for (i = 0; i < nitemset; ++i)
+ if (item_number_is_symbol_number (ritem[itemset[i]]))
+ {
+ symbol_number sym = item_number_as_symbol_number (ritem[itemset[i]]);
+ if (!kernel_size[sym])
+ {
+ shift_symbol[nshifts] = sym;
+ nshifts++;
+ }
+
+ 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 SYM. Create a new state if no equivalent one exists |
+| already. Used by append_states. |
+`--------------------------------------------------------------*/
+
+static state *
+get_state (symbol_number sym, size_t core_size, item_number *core)
+{
+ state *s;
+
+ if (trace_flag & trace_automaton)
+ fprintf (stderr, "Entering get_state, symbol = %d (%s)\n",
+ sym, symbols[sym]->tag);
+
+ 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", s->number);
+
+ return s;
+}
+
+/*---------------------------------------------------------------.
+| 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 *s)
+{
+ int i;
+
+ if (trace_flag & trace_automaton)
+ fprintf (stderr, "Entering append_states, state = %d\n", s->number);
+
+ /* First sort shift_symbol into increasing order. */
+
+ for (i = 1; i < nshifts; i++)
+ {
+ 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_number sym = shift_symbol[i];
+ shiftset[i] = get_state (sym, kernel_size[sym], kernel_base[sym]);
+ }
+}
+
+
+/*----------------------------------------------------------------.
+| Find which rules can be used for reduction transitions from the |
+| current state and make a reductions structure for the state to |
+| record their rule numbers. |
+`----------------------------------------------------------------*/
+
+static void
+save_reductions (state *s)
+{
+ int count = 0;
+ size_t i;
+
+ /* Find and count the active items that represent ends of rules. */
+ for (i = 0; i < nitemset; ++i)
+ {
+ 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 (s, count, redset);
+}
+
+
+/*---------------.
+| Build STATES. |
+`---------------*/
+
+static void
+set_states (void)
+{
+ states = xcalloc (nstates, sizeof *states);
+
+ while (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 *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);
+ }
+ first_state = NULL;
+ last_state = NULL;
+}
+
+
+/*-------------------------------------------------------------------.
+| Compute the nondeterministic finite state machine (see state.h for |
+| details) from the grammar. |
+`-------------------------------------------------------------------*/
+
+void
+generate_states (void)
+{
+ 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. */
+ 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 *s = list->state;
+ if (trace_flag & trace_automaton)
+ fprintf (stderr, "Processing state %d (reached by %s)\n",
+ s->number,
+ symbols[s->accessing_symbol]->tag);
+ /* Set up itemset for the transitions out of this state. itemset gets a
+ vector of all the items that could be accepted next. */
+ closure (s->items, s->nitems);
+ /* Record the reductions allowed out of this state. */
+ save_reductions (s);
+ /* Find the itemsets of the states that shifts can reach. */
+ new_itemsets (s);
+ /* Find or create the core structures for those states. */
+ 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 (s, nshifts, shiftset);
+ }
+
+ /* discard various storage */
+ free_closure ();
+ free_storage ();
+
+ /* Set up STATES. */
+ set_states ();
+}
Property changes on: bison\src\bison\2.4.1\bison-2.4.1-src\src\LR0.c
___________________________________________________________________
Added: svn:eol-style
+ LF
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