X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/7612000cb004ae5b8516e3a34a79ab32050d688e..9ca7f077a0a5ecdd00c5945c7a7bd3cf46e23c13:/src/closure.c?ds=inline
diff --git a/src/closure.c b/src/closure.c
index 6255538f..ff3109ca 100644
--- a/src/closure.c
+++ b/src/closure.c
@@ -1,351 +1,249 @@
-/* Subroutines for bison
- Copyright (C) 1984, 1989 Free Software Foundation, Inc.
+/* Closures for Bison
-This file is part of Bison, the GNU Compiler Compiler.
+ Copyright (C) 1984, 1989, 2000, 2001, 2002, 2004, 2005, 2007 Free
+ Software Foundation, Inc.
-Bison 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 2, or (at your option)
-any later version.
+ This file is part of Bison, the GNU Compiler Compiler.
-Bison 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.
+ 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.
-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, 675 Mass Ave, Cambridge, MA 02139, USA. */
+ 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 . */
-/* subroutines of file LR0.c.
-
-Entry points:
-
- closure (items, n)
-
-Given a vector of item numbers items, of length n,
-set up ruleset and itemset to indicate what rules could be run
-and which items could be accepted when those items are the active ones.
-
-ruleset contains a bit for each rule. closure sets the bits
-for all rules which could potentially describe the next input to be read.
-
-itemset is a vector of item numbers; itemsetend points to just beyond the end
- of the part of it that is significant.
-closure places there the indices of all items which represent units of
-input that could arrive next.
-
- initialize_closure (n)
-
-Allocates the itemset and ruleset vectors,
-and precomputes useful data so that closure can be called.
-n is the number of elements to allocate for itemset.
-
- finalize_closure ()
-
-Frees itemset, ruleset and internal data.
-
-*/
-
-#include
+#include
#include "system.h"
-#include "machine.h"
-#include "alloc.h"
-#include "gram.h"
-
-extern short **derives;
-extern char **tags;
+#include
+#include
+#include
+#include
-void set_fderives();
-void set_firsts();
+#include "closure.h"
+#include "derives.h"
+#include "getargs.h"
+#include "gram.h"
+#include "reader.h"
+#include "symtab.h"
-extern void RTC();
+/* NITEMSET is the size of the array ITEMSET. */
+item_number *itemset;
+size_t nitemset;
-short *itemset;
-short *itemsetend;
-static unsigned *ruleset;
+static bitset ruleset;
/* internal data. See comments before set_fderives and set_firsts. */
-static unsigned *fderives;
-static unsigned *firsts;
-
-/* number of words required to hold a bit for each rule */
-static int rulesetsize;
+static bitsetv fderives = NULL;
+static bitsetv firsts = NULL;
-/* number of words required to hold a bit for each variable */
-static int varsetsize;
+/* Retrieve the FDERIVES/FIRSTS sets of the nonterminals numbered Var. */
+#define FDERIVES(Var) fderives[(Var) - ntokens]
+#define FIRSTS(Var) firsts[(Var) - ntokens]
+
+/*-----------------.
+| Debugging code. |
+`-----------------*/
-void
-initialize_closure(n)
-int n;
+static void
+print_closure (char const *title, item_number *array, size_t size)
{
- itemset = NEW2(n, short);
-
- rulesetsize = WORDSIZE(nrules + 1);
- ruleset = NEW2(rulesetsize, unsigned);
-
- set_fderives();
+ 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);
}
-
-/* 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. */
-void
-set_fderives()
+static void
+print_firsts (void)
{
- register unsigned *rrow;
- register unsigned *vrow;
- register int j;
- register unsigned cword;
- register short *rp;
- register int b;
-
- int ruleno;
- int i;
-
- fderives = NEW2(nvars * rulesetsize, unsigned) - ntokens * rulesetsize;
-
- set_firsts();
-
- rrow = fderives + ntokens * rulesetsize;
+ symbol_number i, j;
+ fprintf (stderr, "FIRSTS\n");
for (i = ntokens; i < nsyms; i++)
{
- vrow = firsts + ((i - ntokens) * varsetsize);
- cword = *vrow++;
- b = 0;
- for (j = ntokens; j < nsyms; j++)
+ bitset_iterator iter;
+ fprintf (stderr, "\t%s firsts\n", symbols[i]->tag);
+ BITSET_FOR_EACH (iter, FIRSTS (i), j, 0)
{
- if (cword & (1 << b))
- {
- rp = derives[j];
- while ((ruleno = *rp++) > 0)
- {
- SETBIT(rrow, ruleno);
- }
- }
-
- b++;
- if (b >= BITS_PER_WORD && j + 1 < nsyms)
- {
- cword = *vrow++;
- b = 0;
- }
+ fprintf (stderr, "\t\t%s\n",
+ symbols[j + ntokens]->tag);
}
-
- rrow += rulesetsize;
}
-
-#ifdef DEBUG
- print_fderives();
-#endif
-
- FREE(firsts);
+ fprintf (stderr, "\n\n");
}
-
-/* set firsts to be an nvars by nvars bit matrix 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, 5 - ntokens] in firsts is set. */
-void
-set_firsts()
+static void
+print_fderives (void)
{
- register unsigned *row;
-/* register int done; JF unused */
- register int symbol;
- register short *sp;
- register int rowsize;
-
int i;
+ rule_number r;
- varsetsize = rowsize = WORDSIZE(nvars);
-
- firsts = NEW2(nvars * rowsize, unsigned);
-
- row = firsts;
+ fprintf (stderr, "FDERIVES\n");
for (i = ntokens; i < nsyms; i++)
{
- sp = derives[i];
- while (*sp >= 0)
+ bitset_iterator iter;
+ fprintf (stderr, "\t%s derives\n", symbols[i]->tag);
+ BITSET_FOR_EACH (iter, FDERIVES (i), r, 0)
{
- symbol = ritem[rrhs[*sp++]];
- if (ISVAR(symbol))
- {
- symbol -= ntokens;
- SETBIT(row, symbol);
- }
+ fprintf (stderr, "\t\t%3d ", r);
+ rule_rhs_print (&rules[r], stderr);
}
-
- row += rowsize;
}
+ 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;
- RTC(firsts, nvars);
+ firsts = bitsetv_create (nvars, nvars, BITSET_FIXED);
-#ifdef DEBUG
- print_firsts();
-#endif
+ 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 ();
}
-
-void
-closure(core, n)
-short *core;
-int n;
+/*-------------------------------------------------------------------.
+| 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)
{
- register int ruleno;
- register unsigned word;
- register short *csp;
- register unsigned *dsp;
- register unsigned *rsp;
-
- short *csend;
- unsigned *rsend;
- int symbol;
- int itemno;
-
- rsp = ruleset;
- rsend = ruleset + rulesetsize;
- csend = core + n;
-
- if (n == 0)
- {
- dsp = fderives + start_symbol * rulesetsize;
- while (rsp < rsend)
- *rsp++ = *dsp++;
- }
- else
- {
- while (rsp < rsend)
- *rsp++ = 0;
+ symbol_number i, j;
+ rule_number k;
- csp = core;
- while (csp < csend)
- {
- symbol = ritem[*csp++];
- if (ISVAR(symbol))
- {
- dsp = fderives + symbol * rulesetsize;
- rsp = ruleset;
- while (rsp < rsend)
- *rsp++ |= *dsp++;
- }
- }
- }
+ fderives = bitsetv_create (nvars, nrules, BITSET_FIXED);
- ruleno = 0;
- itemsetend = itemset;
- csp = core;
- rsp = ruleset;
- while (rsp < rsend)
- {
- word = *rsp++;
- if (word == 0)
- {
- ruleno += BITS_PER_WORD;
- }
- else
- {
- register int b;
-
- for (b = 0; b < BITS_PER_WORD; b++)
- {
- if (word & (1 << b))
- {
- itemno = rrhs[ruleno];
- while (csp < csend && *csp < itemno)
- *itemsetend++ = *csp++;
- *itemsetend++ = itemno;
- }
-
- ruleno++;
- }
- }
- }
+ 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);
- while (csp < csend)
- *itemsetend++ = *csp++;
+ if (trace_flag & trace_sets)
+ print_fderives ();
-#ifdef DEBUG
- print_closure(n);
-#endif
+ bitsetv_free (firsts);
}
+
void
-finalize_closure()
+new_closure (unsigned int n)
{
- FREE(itemset);
- FREE(ruleset);
- FREE(fderives + ntokens * rulesetsize);
-}
-
+ itemset = xnmalloc (n, sizeof *itemset);
+ ruleset = bitset_create (nrules, BITSET_FIXED);
-#ifdef DEBUG
-
-print_closure(n)
-int n;
-{
- register short *isp;
-
- printf("\n\nn = %d\n\n", n);
- for (isp = itemset; isp < itemsetend; isp++)
- printf(" %d\n", *isp);
+ set_fderives ();
}
-print_firsts()
+void
+closure (item_number *core, size_t n)
{
- register int i;
- register int j;
- register unsigned *rowp;
-
- printf(_("\n\n\nFIRSTS\n\n"));
+ /* Index over CORE. */
+ size_t c;
- for (i = ntokens; i < nsyms; i++)
- {
- printf(_("\n\n%s firsts\n\n"), tags[i]);
-
- rowp = firsts + ((i - ntokens) * varsetsize);
-
- for (j = 0; j < nvars; j++)
- if (BITISSET (rowp, j))
- printf(" %s\n", tags[j + ntokens]);
- }
-}
+ /* A bit index over RULESET. */
+ rule_number ruleno;
+ bitset_iterator iter;
+ if (trace_flag & trace_sets)
+ print_closure ("input", core, n);
-print_fderives()
-{
- register int i;
- register int j;
- register unsigned *rp;
+ bitset_zero (ruleset);
- printf(_("\n\n\nFDERIVES\n"));
+ for (c = 0; c < n; ++c)
+ if (ISVAR (ritem[core[c]]))
+ bitset_or (ruleset, ruleset, FDERIVES (ritem[core[c]]));
- for (i = ntokens; i < nsyms; i++)
+ /* 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)
{
- printf(_("\n\n%s derives\n\n"), tags[i]);
- rp = fderives + i * rulesetsize;
+ item_number itemno = rules[ruleno].rhs - ritem;
+ while (c < n && core[c] < itemno)
+ {
+ itemset[nitemset] = core[c];
+ nitemset++;
+ c++;
+ }
+ itemset[nitemset] = itemno;
+ nitemset++;
+ };
- for (j = 0; j <= nrules; j++)
- if (BITISSET (rp, j))
- printf(" %d\n", j);
+ while (c < n)
+ {
+ itemset[nitemset] = core[c];
+ nitemset++;
+ c++;
}
- fflush(stdout);
+ if (trace_flag & trace_sets)
+ print_closure ("output", itemset, nitemset);
}
-#endif
+
+void
+free_closure (void)
+{
+ free (itemset);
+ bitset_free (ruleset);
+ bitsetv_free (fderives);
+}