X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/d0fb370f6686f29d90739486c31f060f1999842a..2fa6973e6f491950d9b0345c1573888eed8e01d7:/src/closure.c diff --git a/src/closure.c b/src/closure.c index b354458e..31073257 100644 --- a/src/closure.c +++ b/src/closure.c @@ -1,67 +1,33 @@ /* Subroutines for bison - Copyright (C) 1984, 1989 Free Software Foundation, Inc. + Copyright (C) 1984, 1989, 2000 Free Software Foundation, Inc. -This file is part of Bison, the GNU Compiler Compiler. + This file is part of Bison, the GNU Compiler Compiler. -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. + 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. -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. + 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. -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. */ + 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, 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 #include "system.h" -#include "machine.h" -#include "new.h" +#include "alloc.h" #include "gram.h" - +#include "closure.h" extern short **derives; extern char **tags; -void set_fderives(); -void set_firsts(); - -extern void RTC(); +extern void RTC PARAMS ((unsigned *, int)); short *itemset; short *itemsetend; @@ -76,43 +42,143 @@ static int rulesetsize; /* number of words required to hold a bit for each variable */ static int varsetsize; + +#if DEBUG +/*-----------------. +| Debugging code. | +`-----------------*/ -void -initialize_closure(n) -int n; +static void +print_closure (int n) { - itemset = NEW2(n, short); + short *isp; - rulesetsize = WORDSIZE(nrules + 1); - ruleset = NEW2(rulesetsize, unsigned); + printf ("\n\nn = %d\n\n", n); + for (isp = itemset; isp < itemsetend; isp++) + printf (" %d\n", *isp); +} - set_fderives(); + +static void +print_firsts (void) +{ + 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]); + + 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) +{ + int i; + int j; + unsigned *rp; + + printf ("\n\n\nFDERIVES\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. */ -void -set_fderives() + 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 + +/*-------------------------------------------------------------------. +| 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 *rrow; - register unsigned *vrow; - register int j; - register unsigned cword; - register short *rp; - register int b; + 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. | +`-------------------------------------------------------------------*/ + +static void +set_fderives (void) +{ + 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; @@ -128,7 +194,7 @@ set_fderives() rp = derives[j]; while ((ruleno = *rp++) > 0) { - SETBIT(rrow, ruleno); + SETBIT (rrow, ruleno); } } @@ -144,69 +210,34 @@ set_fderives() } #ifdef DEBUG - print_fderives(); + print_fderives (); #endif - FREE(firsts); + FREE (firsts); } + - - -/* 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() +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); - - 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; - } + itemset = NEW2 (n, short); - RTC(firsts, nvars); + rulesetsize = WORDSIZE (nrules + 1); + ruleset = NEW2 (rulesetsize, unsigned); -#ifdef DEBUG - print_firsts(); -#endif + set_fderives (); } + void -closure(core, n) -short *core; -int n; +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; @@ -232,7 +263,7 @@ int n; while (csp < csend) { symbol = ritem[*csp++]; - if (ISVAR(symbol)) + if (ISVAR (symbol)) { dsp = fderives + symbol * rulesetsize; rsp = ruleset; @@ -255,7 +286,7 @@ int n; } else { - register int b; + int b; for (b = 0; b < BITS_PER_WORD; b++) { @@ -275,77 +306,16 @@ int n; while (csp < csend) *itemsetend++ = *csp++; -#ifdef DEBUG - print_closure(n); +#if DEBUG + print_closure (n); #endif } void -finalize_closure() -{ - FREE(itemset); - FREE(ruleset); - FREE(fderives + ntokens * rulesetsize); -} - - - -#ifdef DEBUG - -print_closure(n) -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); -} - - - -print_firsts() -{ - 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); } - - - -print_fderives() -{ - 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