/* Subroutines for bison
- Copyright (C) 1984, 1989, 2000 Free Software Foundation, Inc.
+ Copyright 1984, 1989, 2000, 2001 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
-
-/* 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 "system.h"
-#include "alloc.h"
+#include "getargs.h"
+#include "symtab.h"
#include "gram.h"
+#include "reader.h"
+#include "closure.h"
+#include "derives.h"
+#include "warshall.h"
-
-extern short **derives;
-extern char **tags;
-
-extern void initialize_closure PARAMS((int));
-extern void closure PARAMS((short *, int));
-extern void finalize_closure PARAMS((void));
-
-static void set_fderives PARAMS((void));
-static void set_firsts PARAMS((void));
-
-extern void RTC PARAMS((unsigned *, int));
-
+/* NITEMSET is the size of the array ITEMSET. */
short *itemset;
-short *itemsetend;
+int nitemset;
+
static unsigned *ruleset;
/* internal data. See comments before set_fderives and set_firsts. */
static unsigned *fderives;
static unsigned *firsts;
+/* Retrieve the FDERIVES/FIRSTS sets of the nonterminals numbered Var. */
+#define FDERIVES(Var) (fderives + ((Var) - ntokens) * rulesetsize)
+#define FIRSTS(Var) (firsts + ((Var) - ntokens) * varsetsize)
+
/* number of words required to hold a bit for each rule */
static int rulesetsize;
/* number of words required to hold a bit for each variable */
static int varsetsize;
+\f
-#ifdef DEBUG
-static void print_closure PARAMS((int));
-static void print_fderives PARAMS((void));
-static void print_firsts PARAMS((void));
-#endif
+/*-----------------.
+| Debugging code. |
+`-----------------*/
-void
-initialize_closure (int n)
+static void
+print_closure (const char *title, short *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)
+ {
+ short *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. */
static void
-set_fderives (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;
+ int 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++)
- {
- 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;
- }
- }
-
- rrow += rulesetsize;
+ fprintf (stderr, "\t%s firsts\n", symbols[i]->tag);
+ for (j = 0; j < nvars; j++)
+ if (BITISSET (FIRSTS (i), j))
+ fprintf (stderr, "\t\t%d (%s)\n",
+ j + ntokens, symbols[j + ntokens]->tag);
}
-
-#ifdef DEBUG
- print_fderives();
-#endif
-
- FREE(firsts);
+ fprintf (stderr, "\n\n");
}
+static void
+print_fderives (void)
+{
+ int i;
+ int j;
-/* 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.
+ fprintf (stderr, "FDERIVES\n");
- 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. */
+ for (i = ntokens; i < nsyms; i++)
+ {
+ fprintf (stderr, "\t%s derives\n", symbols[i]->tag);
+ for (j = 0; j <= nrules; j++)
+ if (BITISSET (FDERIVES (i), j))
+ {
+ short *rhsp;
+ fprintf (stderr, "\t\t%d:", j - 1);
+ for (rhsp = &ritem[rules[j].rhs]; *rhsp >= 0; ++rhsp)
+ fprintf (stderr, " %s", symbols[*rhsp]->tag);
+ fputc ('\n', stderr);
+ }
+ }
+ fprintf (stderr, "\n\n");
+}
+\f
+/*-------------------------------------------------------------------.
+| 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. |
+`-------------------------------------------------------------------*/
static void
set_firsts (void)
{
- register unsigned *row;
-/* register int done; JF unused */
- register int symbol;
- register short *sp;
- register int rowsize;
+ int i, j;
- int i;
-
- varsetsize = rowsize = WORDSIZE(nvars);
+ varsetsize = WORDSIZE (nvars);
- firsts = NEW2(nvars * rowsize, unsigned);
+ firsts = XCALLOC (unsigned, nvars * varsetsize);
- row = firsts;
for (i = ntokens; i < nsyms; i++)
- {
- sp = derives[i];
- while (*sp >= 0)
- {
- symbol = ritem[rrhs[*sp++]];
- if (ISVAR(symbol))
- {
- symbol -= ntokens;
- SETBIT(row, symbol);
- }
- }
-
- row += rowsize;
- }
+ for (j = 0; derives[i][j] >= 0; ++j)
+ {
+ int symbol = ritem[rules[derives[i][j]].rhs];
+ if (ISVAR (symbol))
+ SETBIT (FIRSTS (i), symbol - ntokens);
+ }
- RTC(firsts, nvars);
+ RTC (firsts, nvars);
-#ifdef DEBUG
- print_firsts ();
-#endif
+ if (trace_flag)
+ 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. |
+`-------------------------------------------------------------------*/
-void
-closure (short *core, int n)
+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;
+ int i, j, k;
- rsp = ruleset;
- rsend = ruleset + rulesetsize;
- csend = core + n;
+ fderives = XCALLOC (unsigned, nvars * rulesetsize);
- if (n == 0)
- {
- dsp = fderives + start_symbol * rulesetsize;
- while (rsp < rsend)
- *rsp++ = *dsp++;
- }
- else
- {
- while (rsp < rsend)
- *rsp++ = 0;
-
- csp = core;
- while (csp < csend)
- {
- symbol = ritem[*csp++];
- if (ISVAR(symbol))
- {
- dsp = fderives + symbol * rulesetsize;
- rsp = ruleset;
- while (rsp < rsend)
- *rsp++ |= *dsp++;
- }
- }
- }
+ set_firsts ();
- 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++;
- }
- }
- }
+ for (i = ntokens; i < nsyms; ++i)
+ for (j = ntokens; j < nsyms; ++j)
+ if (BITISSET (FIRSTS (i), j - ntokens))
+ for (k = 0; derives[j][k] > 0; ++k)
+ SETBIT (FDERIVES (i), derives[j][k]);
- while (csp < csend)
- *itemsetend++ = *csp++;
+ if (trace_flag)
+ print_fderives ();
-#ifdef DEBUG
- print_closure(n);
-#endif
+ XFREE (firsts);
}
-
+\f
void
-finalize_closure (void)
+new_closure (int n)
{
- FREE(itemset);
- FREE(ruleset);
- FREE(fderives + ntokens * rulesetsize);
-}
-
-
+ itemset = XCALLOC (short, n);
-#ifdef DEBUG
+ rulesetsize = WORDSIZE (nrules + 1);
+ ruleset = XCALLOC (unsigned, rulesetsize);
-static void
-print_closure(int n)
-{
- register short *isp;
-
- printf ("\n\nn = %d\n\n", n);
- for (isp = itemset; isp < itemsetend; isp++)
- printf (" %d\n", *isp);
+ set_fderives ();
}
-static void
-print_firsts (void)
+
+void
+closure (short *core, int n)
{
- register int i;
- register int j;
- register unsigned *rowp;
+ /* Index over CORE. */
+ int c;
- printf ("\n\n\nFIRSTS\n\n");
+ /* Index over RULESET. */
+ int r;
- for (i = ntokens; i < nsyms; i++)
- {
- printf ("\n\n%s firsts\n\n", tags[i]);
+ /* A bit index over RULESET. */
+ int ruleno;
- rowp = firsts + ((i - ntokens) * varsetsize);
+ if (trace_flag)
+ print_closure ("input", core, n);
- for (j = 0; j < nvars; j++)
- if (BITISSET (rowp, j))
- printf (" %s\n", tags[j + ntokens]);
+ if (n == 0)
+ {
+ for (r = 0; r < rulesetsize; ++r)
+ ruleset[r] = FDERIVES (start_symbol)[r];
}
-}
-
-
-static void
-print_fderives (void)
-{
- register int i;
- register int j;
- register unsigned *rp;
+ else
+ {
+ for (r = 0; r < rulesetsize; ++r)
+ ruleset[r] = 0;
- printf ("\n\n\nFDERIVES\n");
+ for (c = 0; c < n; ++c)
+ if (ISVAR (ritem[core[c]]))
+ for (r = 0; r < rulesetsize; ++r)
+ ruleset[r] |= FDERIVES (ritem[core[c]])[r];
+ }
- for (i = ntokens; i < nsyms; i++)
+ nitemset = 0;
+ c = 0;
+ for (ruleno = 0; ruleno < nrules + 1; ++ruleno)
+ if (BITISSET (ruleset, ruleno))
+ {
+ int itemno = rules[ruleno].rhs;
+ while (c < n && core[c] < itemno)
+ {
+ itemset[nitemset] = core[c];
+ nitemset++;
+ c++;
+ }
+ itemset[nitemset] = itemno;
+ nitemset++;
+ }
+
+ while (c < n)
{
- printf ("\n\n%s derives\n\n", tags[i]);
- rp = fderives + i * rulesetsize;
-
- for (j = 0; j <= nrules; j++)
- if (BITISSET (rp, j))
- printf (" %d\n", j);
+ itemset[nitemset] = core[c];
+ nitemset++;
+ c++;
}
- fflush(stdout);
+ if (trace_flag)
+ print_closure ("output", itemset, nitemset);
}
-#endif
+
+void
+free_closure (void)
+{
+ XFREE (itemset);
+ XFREE (ruleset);
+ XFREE (fderives);
+}
projects / bison.git / blobdiff