/* 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. */
+#include "system.h"
+#include "getargs.h"
+#include "gram.h"
+#include "reader.h"
+#include "closure.h"
+#include "derives.h"
+#include "warshall.h"
-/* Subroutines of file LR0.c.
+/* ITEMSETSIZE is the size of the array ITEMSET. */
+short *itemset;
+int itemsetsize;
-Entry points:
+static unsigned *ruleset;
- closure (items, n)
+/* internal data. See comments before set_fderives and set_firsts. */
+static unsigned *fderives;
+static unsigned *firsts;
-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.
+#define FDERIVES(Symbol) (fderives + (Symbol) * rulesetsize)
+#define FIRSTS(Symbol) (firsts + (Symbol) * varsetsize)
-ruleset contains a bit for each rule. closure sets the bits for all
-rules which could potentially describe the next input to be read.
+/* number of words required to hold a bit for each rule */
+static int rulesetsize;
-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.
+/* number of words required to hold a bit for each variable */
+static int varsetsize;
+\f
- initialize_closure (n)
+/*-----------------.
+| Debugging code. |
+`-----------------*/
-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.
+static void
+print_closure (int n)
+{
+ int i;
+ fprintf (stderr, "n = %d\n", n);
+ for (i = 0; i < itemsetsize; ++i)
+ fprintf (stderr, " %d\n", itemset[i]);
+ fprintf (stderr, "\n\n");
+}
- finalize_closure ()
-Frees itemset, ruleset and internal data.
+static void
+print_firsts (void)
+{
+ int i;
+ int j;
+ unsigned *rowp;
-*/
+ fprintf (stderr, "FIRSTS\n");
-#include "system.h"
-#include "alloc.h"
-#include "gram.h"
+ for (i = ntokens; i < nsyms; i++)
+ {
+ fprintf (stderr, "\t%s firsts\n", tags[i]);
+ rowp = FIRSTS (i - ntokens);
-extern short **derives;
-extern char **tags;
+ for (j = 0; j < nvars; j++)
+ if (BITISSET (rowp, j))
+ fprintf (stderr, "\t\t%d (%s)\n", j + ntokens, tags[j + ntokens]);
+ }
+ fprintf (stderr, "\n\n");
+}
-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));
+static void
+print_fderives (void)
+{
+ int i;
+ int j;
+ unsigned *rp;
-extern void RTC PARAMS((unsigned *, int));
+ fprintf (stderr, "FDERIVES\n");
-short *itemset;
-short *itemsetend;
-static unsigned *ruleset;
+ for (i = ntokens; i < nsyms; i++)
+ {
+ fprintf (stderr, "\t%s derives\n", tags[i]);
+ rp = FDERIVES (i);
-/* internal data. See comments before set_fderives and set_firsts. */
-static unsigned *fderives;
-static unsigned *firsts;
+ for (j = 0; j <= nrules; j++)
+ if (BITISSET (rp, j))
+ {
+ short *rhsp;
+ fprintf (stderr, "\t\t%d:", j);
+ for (rhsp = ritem + rule_table[j].rhs; *rhsp > 0; ++rhsp)
+ fprintf (stderr, " %s", tags[*rhsp]);
+ 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. |
+`-------------------------------------------------------------------*/
-/* number of words required to hold a bit for each rule */
-static int rulesetsize;
+static void
+set_firsts (void)
+{
+ unsigned *row;
+ int symbol;
+ short *sp;
+ int rowsize;
-/* number of words required to hold a bit for each variable */
-static int varsetsize;
+ int i;
-#ifdef DEBUG
-static void print_closure PARAMS((int));
-static void print_fderives PARAMS((void));
-static void print_firsts PARAMS((void));
-#endif
+ varsetsize = rowsize = WORDSIZE (nvars);
-void
-initialize_closure (int n)
-{
- itemset = NEW2(n, short);
+ firsts = XCALLOC (unsigned, nvars * rowsize);
- rulesetsize = WORDSIZE(nrules + 1);
- ruleset = NEW2(rulesetsize, unsigned);
+ row = firsts;
+ for (i = ntokens; i < nsyms; i++)
+ {
+ sp = derives[i];
+ while (*sp >= 0)
+ {
+ symbol = ritem[rule_table[*sp++].rhs];
+ if (ISVAR (symbol))
+ {
+ symbol -= ntokens;
+ SETBIT (row, symbol);
+ }
+ }
- set_fderives();
-}
+ row += rowsize;
+ }
+
+ RTC (firsts, nvars);
+ 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. |
+`-------------------------------------------------------------------*/
-/* 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 unsigned *rrow;
- register unsigned *vrow;
- register int j;
- register unsigned cword;
- register short *rp;
- register int b;
+ unsigned *rrow;
+ unsigned *vrow;
+ int j;
+ unsigned cword;
+ short *rp;
+ int b;
int ruleno;
int i;
- fderives = NEW2(nvars * rulesetsize, unsigned) - ntokens * rulesetsize;
+ fderives = XCALLOC (unsigned, nvars * rulesetsize) - ntokens * rulesetsize;
- set_firsts();
+ set_firsts ();
- rrow = fderives + ntokens * rulesetsize;
+ rrow = FDERIVES (ntokens);
for (i = ntokens; i < nsyms; i++)
{
- vrow = firsts + ((i - ntokens) * varsetsize);
+ vrow = FIRSTS (i - ntokens);
cword = *vrow++;
b = 0;
for (j = ntokens; j < nsyms; j++)
{
rp = derives[j];
while ((ruleno = *rp++) > 0)
- {
- SETBIT(rrow, ruleno);
- }
+ SETBIT (rrow, ruleno);
}
b++;
rrow += rulesetsize;
}
-#ifdef DEBUG
- print_fderives();
-#endif
+ if (trace_flag)
+ print_fderives ();
- FREE(firsts);
+ XFREE (firsts);
}
+\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)
+void
+new_closure (int n)
{
- register unsigned *row;
-/* register int done; JF unused */
- register int symbol;
- register short *sp;
- register int rowsize;
-
- int i;
-
- varsetsize = rowsize = WORDSIZE(nvars);
+ itemset = XCALLOC (short, n);
- firsts = NEW2(nvars * rowsize, unsigned);
+ rulesetsize = WORDSIZE (nrules + 1);
+ ruleset = XCALLOC (unsigned, rulesetsize);
- 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;
- }
-
- RTC(firsts, nvars);
-
-#ifdef DEBUG
- print_firsts ();
-#endif
+ set_fderives ();
}
+
void
closure (short *core, int n)
{
- register int ruleno;
- register unsigned word;
- register short *csp;
- register unsigned *dsp;
- register unsigned *rsp;
-
- short *csend;
- unsigned *rsend;
- int symbol;
+ int ruleno;
+ short *csp;
+
int itemno;
+ int i;
- rsp = ruleset;
- rsend = ruleset + rulesetsize;
- csend = core + n;
+ if (trace_flag)
+ {
+ fprintf (stderr, "Entering closure (items = {");
+ for (i = 0; i < n; ++i)
+ fprintf (stderr, " %d ", core[i]);
+ fprintf (stderr, "}, nitems = %d)\n", n);
+ }
if (n == 0)
{
- dsp = fderives + start_symbol * rulesetsize;
- while (rsp < rsend)
- *rsp++ = *dsp++;
+ for (i = 0; i < rulesetsize; ++i)
+ ruleset[i] = FDERIVES (start_symbol)[i];
}
else
{
- while (rsp < rsend)
- *rsp++ = 0;
+ for (i = 0; i < rulesetsize; ++i)
+ ruleset[i] = 0;
- csp = core;
- while (csp < csend)
+ for (i = 0; i < n; ++i)
{
- symbol = ritem[*csp++];
- if (ISVAR(symbol))
+ int symbol = ritem[core[i]];
+ if (ISVAR (symbol))
{
- dsp = fderives + symbol * rulesetsize;
- rsp = ruleset;
- while (rsp < rsend)
- *rsp++ |= *dsp++;
+ int j;
+ for (j = 0; j < rulesetsize; ++j)
+ ruleset[j] |= FDERIVES (symbol)[j];
}
}
}
ruleno = 0;
- itemsetend = itemset;
+ itemsetsize = 0;
csp = core;
- rsp = ruleset;
- while (rsp < rsend)
+ for (i = 0; i < rulesetsize; ++i)
{
- word = *rsp++;
+ int word = ruleset[i];
if (word == 0)
{
ruleno += BITS_PER_WORD;
}
else
{
- register int b;
+ 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;
+ itemno = rule_table[ruleno].rhs;
+ while (csp < (core + n) && *csp < itemno)
+ itemset[itemsetsize++] = *csp++;
+ itemset[itemsetsize++] = itemno;
}
ruleno++;
}
}
- while (csp < csend)
- *itemsetend++ = *csp++;
+ while (csp < (core + n))
+ itemset[itemsetsize++] = *csp++;
-#ifdef DEBUG
- print_closure(n);
-#endif
+ if (trace_flag)
+ print_closure (n);
}
void
-finalize_closure (void)
-{
- FREE(itemset);
- FREE(ruleset);
- FREE(fderives + ntokens * rulesetsize);
-}
-
-
-
-#ifdef DEBUG
-
-static void
-print_closure(int n)
+free_closure (void)
{
- register short *isp;
-
- printf ("\n\nn = %d\n\n", n);
- for (isp = itemset; isp < itemsetend; isp++)
- printf (" %d\n", *isp);
+ XFREE (itemset);
+ XFREE (ruleset);
+ XFREE (fderives + ntokens * rulesetsize);
}
-
-
-static void
-print_firsts (void)
-{
- register int i;
- register int j;
- register unsigned *rowp;
-
- printf ("\n\n\nFIRSTS\n\n");
-
- 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]);
- }
-}
-
-
-static void
-print_fderives (void)
-{
- register int i;
- register int j;
- register unsigned *rp;
-
- printf ("\n\n\nFDERIVES\n");
-
- for (i = ntokens; i < nsyms; i++)
- {
- 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);
- }
-
- fflush(stdout);
-}
-
-#endif
projects / bison.git / blobdiff