Index: bison/src/bison/2.4.1/bison-2.4.1-src/src/closure.c |
=================================================================== |
--- bison/src/bison/2.4.1/bison-2.4.1-src/src/closure.c (revision 0) |
+++ bison/src/bison/2.4.1/bison-2.4.1-src/src/closure.c (revision 0) |
@@ -0,0 +1,249 @@ |
+/* Closures for Bison |
+ |
+ Copyright (C) 1984, 1989, 2000, 2001, 2002, 2004, 2005, 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/>. */ |
+ |
+#include <config.h> |
+#include "system.h" |
+ |
+#include <bitset.h> |
+#include <bitsetv-print.h> |
+#include <bitsetv.h> |
+#include <quotearg.h> |
+ |
+#include "closure.h" |
+#include "derives.h" |
+#include "getargs.h" |
+#include "gram.h" |
+#include "reader.h" |
+#include "symtab.h" |
+ |
+/* NITEMSET is the size of the array ITEMSET. */ |
+item_number *itemset; |
+size_t nitemset; |
+ |
+static bitset ruleset; |
+ |
+/* internal data. See comments before set_fderives and set_firsts. */ |
+static bitsetv fderives = NULL; |
+static bitsetv firsts = NULL; |
+ |
+/* Retrieve the FDERIVES/FIRSTS sets of the nonterminals numbered Var. */ |
+#define FDERIVES(Var) fderives[(Var) - ntokens] |
+#define FIRSTS(Var) firsts[(Var) - ntokens] |
+ |
+ |
+/*-----------------. |
+| Debugging code. | |
+`-----------------*/ |
+ |
+static void |
+print_closure (char const *title, item_number *array, size_t size) |
+{ |
+ size_t i; |
+ fprintf (stderr, "Closure: %s\n", title); |
+ for (i = 0; i < size; ++i) |
+ { |
+ item_number *rp; |
+ fprintf (stderr, " %2d: .", array[i]); |
+ for (rp = &ritem[array[i]]; *rp >= 0; ++rp) |
+ fprintf (stderr, " %s", symbols[*rp]->tag); |
+ fprintf (stderr, " (rule %d)\n", -*rp - 1); |
+ } |
+ fputs ("\n\n", stderr); |
+} |
+ |
+ |
+static void |
+print_firsts (void) |
+{ |
+ symbol_number i, j; |
+ |
+ fprintf (stderr, "FIRSTS\n"); |
+ for (i = ntokens; i < nsyms; i++) |
+ { |
+ bitset_iterator iter; |
+ fprintf (stderr, "\t%s firsts\n", symbols[i]->tag); |
+ BITSET_FOR_EACH (iter, FIRSTS (i), j, 0) |
+ { |
+ fprintf (stderr, "\t\t%s\n", |
+ symbols[j + ntokens]->tag); |
+ } |
+ } |
+ fprintf (stderr, "\n\n"); |
+} |
+ |
+ |
+static void |
+print_fderives (void) |
+{ |
+ int i; |
+ rule_number r; |
+ |
+ fprintf (stderr, "FDERIVES\n"); |
+ for (i = ntokens; i < nsyms; i++) |
+ { |
+ bitset_iterator iter; |
+ fprintf (stderr, "\t%s derives\n", symbols[i]->tag); |
+ BITSET_FOR_EACH (iter, FDERIVES (i), r, 0) |
+ { |
+ fprintf (stderr, "\t\t%3d ", r); |
+ rule_rhs_print (&rules[r], stderr); |
+ } |
+ } |
+ fprintf (stderr, "\n\n"); |
+} |
+ |
+/*------------------------------------------------------------------. |
+| Set FIRSTS to be an NVARS array of NVARS bitsets indicating which | |
+| items can represent the beginning of the input corresponding to | |
+| which other items. | |
+| | |
+| For example, if some rule expands symbol 5 into the sequence of | |
+| symbols 8 3 20, the symbol 8 can be the beginning of the data for | |
+| symbol 5, so the bit [8 - ntokens] in first[5 - ntokens] (= FIRST | |
+| (5)) is set. | |
+`------------------------------------------------------------------*/ |
+ |
+static void |
+set_firsts (void) |
+{ |
+ symbol_number i, j; |
+ |
+ firsts = bitsetv_create (nvars, nvars, BITSET_FIXED); |
+ |
+ for (i = ntokens; i < nsyms; i++) |
+ for (j = 0; derives[i - ntokens][j]; ++j) |
+ { |
+ item_number sym = derives[i - ntokens][j]->rhs[0]; |
+ if (ISVAR (sym)) |
+ bitset_set (FIRSTS (i), sym - ntokens); |
+ } |
+ |
+ if (trace_flag & trace_sets) |
+ bitsetv_matrix_dump (stderr, "RTC: Firsts Input", firsts); |
+ bitsetv_reflexive_transitive_closure (firsts); |
+ if (trace_flag & trace_sets) |
+ bitsetv_matrix_dump (stderr, "RTC: Firsts Output", firsts); |
+ |
+ if (trace_flag & trace_sets) |
+ print_firsts (); |
+} |
+ |
+/*-------------------------------------------------------------------. |
+| Set FDERIVES to an NVARS by NRULES matrix of bits indicating which | |
+| rules can help derive the beginning of the data for each | |
+| nonterminal. | |
+| | |
+| For example, if symbol 5 can be derived as the sequence of symbols | |
+| 8 3 20, and one of the rules for deriving symbol 8 is rule 4, then | |
+| the [5 - NTOKENS, 4] bit in FDERIVES is set. | |
+`-------------------------------------------------------------------*/ |
+ |
+static void |
+set_fderives (void) |
+{ |
+ symbol_number i, j; |
+ rule_number k; |
+ |
+ fderives = bitsetv_create (nvars, nrules, BITSET_FIXED); |
+ |
+ set_firsts (); |
+ |
+ for (i = ntokens; i < nsyms; ++i) |
+ for (j = ntokens; j < nsyms; ++j) |
+ if (bitset_test (FIRSTS (i), j - ntokens)) |
+ for (k = 0; derives[j - ntokens][k]; ++k) |
+ bitset_set (FDERIVES (i), derives[j - ntokens][k]->number); |
+ |
+ if (trace_flag & trace_sets) |
+ print_fderives (); |
+ |
+ bitsetv_free (firsts); |
+} |
+ |
+ |
+ |
+void |
+new_closure (unsigned int n) |
+{ |
+ itemset = xnmalloc (n, sizeof *itemset); |
+ |
+ ruleset = bitset_create (nrules, BITSET_FIXED); |
+ |
+ set_fderives (); |
+} |
+ |
+ |
+ |
+void |
+closure (item_number *core, size_t n) |
+{ |
+ /* Index over CORE. */ |
+ size_t c; |
+ |
+ /* A bit index over RULESET. */ |
+ rule_number ruleno; |
+ |
+ bitset_iterator iter; |
+ |
+ if (trace_flag & trace_sets) |
+ print_closure ("input", core, n); |
+ |
+ bitset_zero (ruleset); |
+ |
+ for (c = 0; c < n; ++c) |
+ if (ISVAR (ritem[core[c]])) |
+ bitset_or (ruleset, ruleset, FDERIVES (ritem[core[c]])); |
+ |
+ /* core is sorted on item index in ritem, which is sorted on rule number. |
+ Compute itemset with the same sort. */ |
+ nitemset = 0; |
+ c = 0; |
+ BITSET_FOR_EACH (iter, ruleset, ruleno, 0) |
+ { |
+ item_number itemno = rules[ruleno].rhs - ritem; |
+ while (c < n && core[c] < itemno) |
+ { |
+ itemset[nitemset] = core[c]; |
+ nitemset++; |
+ c++; |
+ } |
+ itemset[nitemset] = itemno; |
+ nitemset++; |
+ }; |
+ |
+ while (c < n) |
+ { |
+ itemset[nitemset] = core[c]; |
+ nitemset++; |
+ c++; |
+ } |
+ |
+ if (trace_flag & trace_sets) |
+ print_closure ("output", itemset, nitemset); |
+} |
+ |
+ |
+void |
+free_closure (void) |
+{ |
+ free (itemset); |
+ bitset_free (ruleset); |
+ bitsetv_free (fderives); |
+} |
Property changes on: bison\src\bison\2.4.1\bison-2.4.1-src\src\closure.c |
___________________________________________________________________ |
Added: svn:eol-style |
+ LF |