X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/499daa504f93cef3d1d2054634f021d63761c6f9..2fa6973e6f491950d9b0345c1573888eed8e01d7:/src/closure.c diff --git a/src/closure.c b/src/closure.c index 4e6fee00..31073257 100644 --- a/src/closure.c +++ b/src/closure.c @@ -19,52 +19,15 @@ 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; @@ -79,47 +42,143 @@ static int rulesetsize; /* number of words required to hold a bit for each variable */ static int varsetsize; + +#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 + +/*-------------------------------------------------------------------. +| 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; @@ -135,7 +194,7 @@ set_fderives (void) rp = derives[j]; while ((ruleno = *rp++) > 0) { - SETBIT(rrow, ruleno); + SETBIT (rrow, ruleno); } } @@ -151,71 +210,34 @@ set_fderives (void) } #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. */ - -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; @@ -241,7 +263,7 @@ closure (short *core, int n) while (csp < csend) { symbol = ritem[*csp++]; - if (ISVAR(symbol)) + if (ISVAR (symbol)) { dsp = fderives + symbol * rulesetsize; rsp = ruleset; @@ -264,7 +286,7 @@ closure (short *core, int n) } else { - register int b; + int b; for (b = 0; b < BITS_PER_WORD; b++) { @@ -284,77 +306,16 @@ closure (short *core, int n) 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