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 "gram.h"
-
+#include "closure.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));
+extern void RTC PARAMS ((unsigned *, int));
short *itemset;
short *itemsetend;
/* number of words required to hold a bit for each variable */
static int varsetsize;
+\f
+#if DEBUG
-#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 (int n)
+{
+ short *isp;
+
+ printf ("\n\nn = %d\n\n", n);
+ for (isp = itemset; isp < itemsetend; isp++)
+ printf (" %d\n", *isp);
+}
+
+
+static void
+print_firsts (void)
{
- itemset = NEW2(n, short);
+ int i;
+ int j;
+ unsigned *rowp;
+
+ printf ("\n\n\nFIRSTS\n\n");
+
+ for (i = ntokens; i < nsyms; i++)
+ {
+ printf ("\n\n%s firsts\n\n", tags[i]);
- rulesetsize = WORDSIZE(nrules + 1);
- ruleset = NEW2(rulesetsize, unsigned);
+ rowp = firsts + ((i - ntokens) * varsetsize);
- set_fderives();
+ for (j = 0; j < nvars; j++)
+ if (BITISSET (rowp, j))
+ printf (" %s\n", tags[j + ntokens]);
+ }
}
+static void
+print_fderives (void)
+{
+ int i;
+ int j;
+ 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
+\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)
+{
+ unsigned *row;
+ int symbol;
+ short *sp;
+ int rowsize;
+
+ int i;
+
+ varsetsize = rowsize = WORDSIZE (nvars);
+
+ firsts = NEW2 (nvars * rowsize, unsigned);
+
+ 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 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 = NEW2 (nvars * rulesetsize, unsigned) - ntokens * rulesetsize;
- set_firsts();
+ set_firsts ();
rrow = fderives + ntokens * rulesetsize;
rp = derives[j];
while ((ruleno = *rp++) > 0)
{
- SETBIT(rrow, ruleno);
+ SETBIT (rrow, ruleno);
}
}
}
#ifdef DEBUG
- print_fderives();
+ print_fderives ();
#endif
- FREE(firsts);
+ FREE (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;
+ itemset = NEW2 (n, short);
- varsetsize = rowsize = WORDSIZE(nvars);
+ rulesetsize = WORDSIZE (nrules + 1);
+ ruleset = NEW2 (rulesetsize, unsigned);
- firsts = NEW2(nvars * rowsize, unsigned);
-
- 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;
+ int ruleno;
+ unsigned word;
+ short *csp;
+ unsigned *dsp;
+ unsigned *rsp;
short *csend;
unsigned *rsend;
while (csp < csend)
{
symbol = ritem[*csp++];
- if (ISVAR(symbol))
+ if (ISVAR (symbol))
{
dsp = fderives + symbol * rulesetsize;
rsp = ruleset;
}
else
{
- register int b;
+ int b;
for (b = 0; b < BITS_PER_WORD; b++)
{
while (csp < csend)
*itemsetend++ = *csp++;
-#ifdef DEBUG
- print_closure(n);
+#if DEBUG
+ print_closure (n);
#endif
}
void
-finalize_closure (void)
-{
- FREE(itemset);
- FREE(ruleset);
- FREE(fderives + ntokens * rulesetsize);
-}
-
-
-
-#ifdef DEBUG
-
-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);
-}
-
-
-static void
-print_firsts (void)
+free_closure (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]);
- }
+ FREE (itemset);
+ FREE (ruleset);
+ FREE (fderives + ntokens * rulesetsize);
}
-
-
-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