X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/a0b76449c7ebb01064f6e091715819f7519c90b2..41930e7ad89f9a889b1c00fbd2842dded01ada1a:/src/nullable.c?ds=sidebyside diff --git a/src/nullable.c b/src/nullable.c index 1a96bef2..7ee66120 100644 --- a/src/nullable.c +++ b/src/nullable.c @@ -1,28 +1,29 @@ -/* Part of the bison parser generator, - Copyright (C) 1984, 1989, 2000, 2001, 2002 Free Software Foundation, Inc. +/* Calculate which nonterminals can expand into the null string for Bison. + + Copyright (C) 1984, 1989, 2000, 2001, 2002, 2003, 2004, 2005, 2006 + Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. - Bison is free software; you can redistribute it and/or modify + This program 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. + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. - Bison is distributed in the hope that it will be useful, + This program 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, Inc., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ + along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* Set up NULLABLE, a vector saying which nonterminals can expand into the null string. NULLABLE[I - NTOKENS] is nonzero if symbol I can do so. */ +#include <config.h> #include "system.h" #include "getargs.h" @@ -46,7 +47,8 @@ nullable_print (FILE *out) int i; fputs ("NULLABLE\n", out); for (i = ntokens; i < nsyms; i++) - fprintf (out, "\t%s: %s\n", symbols[i]->tag, nullable[i] ? "yes" : "no"); + fprintf (out, "\t%s: %s\n", symbols[i]->tag, + nullable[i - ntokens] ? "yes" : "no"); fputs ("\n\n", out); } @@ -58,16 +60,16 @@ nullable_compute (void) symbol_number *s2; rule_list *p; - symbol_number *squeue = XCALLOC (symbol_number, nvars); - short *rcount = XCALLOC (short, nrules); + symbol_number *squeue = xnmalloc (nvars, sizeof *squeue); + size_t *rcount = xcalloc (nrules, sizeof *rcount); /* RITEM contains all the rules, including useless productions. Hence we must allocate room for useless nonterminals too. */ - rule_list **rsets = XCALLOC (rule_list *, nvars) - ntokens; + rule_list **rsets = xcalloc (nvars, sizeof *rsets); /* This is said to be more elements than we actually use. Supposedly NRITEMS - NRULES is enough. But why take the risk? */ - rule_list *relts = XCALLOC (rule_list, nritems + nvars + 1); + rule_list *relts = xnmalloc (nritems + nvars + 1, sizeof *relts); - nullable = XCALLOC (bool, nvars) - ntokens; + nullable = xcalloc (nvars, sizeof *nullable); s1 = s2 = squeue; p = relts; @@ -79,53 +81,54 @@ nullable_compute (void) if (rules_ruleno->rhs[0] >= 0) { /* This rule has a non empty RHS. */ - item_number *r = NULL; - int any_tokens = 0; - for (r = rules_ruleno->rhs; *r >= 0; ++r) - if (ISTOKEN (*r)) - any_tokens = 1; + item_number *rp = NULL; + bool any_tokens = false; + for (rp = rules_ruleno->rhs; *rp >= 0; ++rp) + if (ISTOKEN (*rp)) + any_tokens = true; /* This rule has only nonterminals: schedule it for the second pass. */ if (!any_tokens) - for (r = rules_ruleno->rhs; *r >= 0; ++r) + for (rp = rules_ruleno->rhs; *rp >= 0; ++rp) { rcount[ruleno]++; - p->next = rsets[*r]; + p->next = rsets[*rp - ntokens]; p->value = rules_ruleno; - rsets[*r] = p; + rsets[*rp - ntokens] = p; p++; } } else { /* This rule has an empty RHS. */ - if (item_number_as_rule_number (rules_ruleno->rhs[0]) != ruleno) - abort (); - if (rules_ruleno->useful && !nullable[rules_ruleno->lhs->number]) + aver (item_number_as_rule_number (rules_ruleno->rhs[0]) + == ruleno); + if (rules_ruleno->useful + && ! nullable[rules_ruleno->lhs->number - ntokens]) { - nullable[rules_ruleno->lhs->number] = 1; + nullable[rules_ruleno->lhs->number - ntokens] = true; *s2++ = rules_ruleno->lhs->number; } } } while (s1 < s2) - for (p = rsets[*s1++]; p; p = p->next) + for (p = rsets[*s1++ - ntokens]; p; p = p->next) { rule *r = p->value; if (--rcount[r->number] == 0) - if (r->useful && !nullable[r->lhs->number]) + if (r->useful && ! nullable[r->lhs->number - ntokens]) { - nullable[r->lhs->number] = 1; + nullable[r->lhs->number - ntokens] = true; *s2++ = r->lhs->number; } } - XFREE (squeue); - XFREE (rcount); - XFREE (rsets + ntokens); - XFREE (relts); + free (squeue); + free (rcount); + free (rsets); + free (relts); if (trace_flag & trace_sets) nullable_print (stderr); @@ -135,5 +138,5 @@ nullable_compute (void) void nullable_free (void) { - XFREE (nullable + ntokens); + free (nullable); }