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Unified Diff: bison/src/bison/2.4.1/bison-2.4.1-src/src/conflicts.c

Issue 10807020: Add native Windows binary for bison. (Closed) Base URL: svn://chrome-svn/chrome/trunk/deps/third_party/
Patch Set: Created 8 years, 5 months ago
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Index: bison/src/bison/2.4.1/bison-2.4.1-src/src/conflicts.c
===================================================================
--- bison/src/bison/2.4.1/bison-2.4.1-src/src/conflicts.c (revision 0)
+++ bison/src/bison/2.4.1/bison-2.4.1-src/src/conflicts.c (revision 0)
@@ -0,0 +1,628 @@
+/* Find and resolve or report lookahead conflicts for bison,
+
+ Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
+ 2007 Free Software Foundation, Inc.
+
+ This file is part of Bison, the GNU Compiler Compiler.
+
+ 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 3 of the License, or
+ (at your option) any later version.
+
+ 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 this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include "system.h"
+
+#include <bitset.h>
+
+#include "LR0.h"
+#include "complain.h"
+#include "conflicts.h"
+#include "files.h"
+#include "getargs.h"
+#include "gram.h"
+#include "lalr.h"
+#include "print-xml.h"
+#include "reader.h"
+#include "state.h"
+#include "symtab.h"
+
+/* -1 stands for not specified. */
+int expected_sr_conflicts = -1;
+int expected_rr_conflicts = -1;
+static char *conflicts;
+static struct obstack solved_conflicts_obstack;
+static struct obstack solved_conflicts_xml_obstack;
+
+static bitset shift_set;
+static bitset lookahead_set;
+
+
+
+enum conflict_resolution
+ {
+ shift_resolution,
+ reduce_resolution,
+ left_resolution,
+ right_resolution,
+ nonassoc_resolution
+ };
+
+
+/*----------------------------------------------------------------.
+| Explain how an SR conflict between TOKEN and RULE was resolved: |
+| RESOLUTION. |
+`----------------------------------------------------------------*/
+
+static inline void
+log_resolution (rule *r, symbol_number token,
+ enum conflict_resolution resolution)
+{
+ if (report_flag & report_solved_conflicts)
+ {
+ /* The description of the resolution. */
+ switch (resolution)
+ {
+ case shift_resolution:
+ case right_resolution:
+ obstack_fgrow2 (&solved_conflicts_obstack,
+ _(" Conflict between rule %d and token %s"
+ " resolved as shift"),
+ r->number,
+ symbols[token]->tag);
+ break;
+
+ case reduce_resolution:
+ case left_resolution:
+ obstack_fgrow2 (&solved_conflicts_obstack,
+ _(" Conflict between rule %d and token %s"
+ " resolved as reduce"),
+ r->number,
+ symbols[token]->tag);
+ break;
+
+ case nonassoc_resolution:
+ obstack_fgrow2 (&solved_conflicts_obstack,
+ _(" Conflict between rule %d and token %s"
+ " resolved as an error"),
+ r->number,
+ symbols[token]->tag);
+ break;
+ }
+
+ /* The reason. */
+ switch (resolution)
+ {
+ case shift_resolution:
+ obstack_fgrow2 (&solved_conflicts_obstack,
+ " (%s < %s)",
+ r->prec->tag,
+ symbols[token]->tag);
+ break;
+
+ case reduce_resolution:
+ obstack_fgrow2 (&solved_conflicts_obstack,
+ " (%s < %s)",
+ symbols[token]->tag,
+ r->prec->tag);
+ break;
+
+ case left_resolution:
+ obstack_fgrow1 (&solved_conflicts_obstack,
+ " (%%left %s)",
+ symbols[token]->tag);
+ break;
+
+ case right_resolution:
+ obstack_fgrow1 (&solved_conflicts_obstack,
+ " (%%right %s)",
+ symbols[token]->tag);
+ break;
+
+ case nonassoc_resolution:
+ obstack_fgrow1 (&solved_conflicts_obstack,
+ " (%%nonassoc %s)",
+ symbols[token]->tag);
+ break;
+ }
+
+ obstack_sgrow (&solved_conflicts_obstack, ".\n");
+ }
+
+ /* XML report */
+ if (xml_flag)
+ {
+ /* The description of the resolution. */
+ switch (resolution)
+ {
+ case shift_resolution:
+ case right_resolution:
+ obstack_fgrow2 (&solved_conflicts_xml_obstack,
+ " <resolution rule=\"%d\" symbol=\"%s\""
+ " type=\"shift\">",
+ r->number,
+ xml_escape (symbols[token]->tag));
+ break;
+
+ case reduce_resolution:
+ case left_resolution:
+ obstack_fgrow2 (&solved_conflicts_xml_obstack,
+ " <resolution rule=\"%d\" symbol=\"%s\""
+ " type=\"reduce\">",
+ r->number,
+ xml_escape (symbols[token]->tag));
+ break;
+
+ case nonassoc_resolution:
+ obstack_fgrow2 (&solved_conflicts_xml_obstack,
+ " <resolution rule=\"%d\" symbol=\"%s\""
+ " type=\"error\">",
+ r->number,
+ xml_escape (symbols[token]->tag));
+ break;
+ }
+
+ /* The reason. */
+ switch (resolution)
+ {
+ case shift_resolution:
+ obstack_fgrow2 (&solved_conflicts_xml_obstack,
+ "%s &lt; %s",
+ xml_escape_n (0, r->prec->tag),
+ xml_escape_n (1, symbols[token]->tag));
+ break;
+
+ case reduce_resolution:
+ obstack_fgrow2 (&solved_conflicts_xml_obstack,
+ "%s &lt; %s",
+ xml_escape_n (0, symbols[token]->tag),
+ xml_escape_n (1, r->prec->tag));
+ break;
+
+ case left_resolution:
+ obstack_fgrow1 (&solved_conflicts_xml_obstack,
+ "%%left %s",
+ xml_escape (symbols[token]->tag));
+ break;
+
+ case right_resolution:
+ obstack_fgrow1 (&solved_conflicts_xml_obstack,
+ "%%right %s",
+ xml_escape (symbols[token]->tag));
+ break;
+
+ case nonassoc_resolution:
+ obstack_fgrow1 (&solved_conflicts_xml_obstack,
+ "%%nonassoc %s",
+ xml_escape (symbols[token]->tag));
+ break;
+ }
+
+ obstack_sgrow (&solved_conflicts_xml_obstack, "</resolution>\n");
+ }
+}
+
+
+/*------------------------------------------------------------------.
+| Turn off the shift recorded for the specified token in the |
+| specified state. Used when we resolve a shift-reduce conflict in |
+| favor of the reduction or as an error (%nonassoc). |
+`------------------------------------------------------------------*/
+
+static void
+flush_shift (state *s, int token)
+{
+ transitions *trans = s->transitions;
+ int i;
+
+ bitset_reset (lookahead_set, token);
+ for (i = 0; i < trans->num; i++)
+ if (!TRANSITION_IS_DISABLED (trans, i)
+ && TRANSITION_SYMBOL (trans, i) == token)
+ TRANSITION_DISABLE (trans, i);
+}
+
+
+/*--------------------------------------------------------------------.
+| Turn off the reduce recorded for the specified token in the |
+| specified lookahead set. Used when we resolve a shift-reduce |
+| conflict in favor of the shift or as an error (%nonassoc). |
+`--------------------------------------------------------------------*/
+
+static void
+flush_reduce (bitset lookahead_tokens, int token)
+{
+ bitset_reset (lookahead_tokens, token);
+}
+
+
+/*------------------------------------------------------------------.
+| Attempt to resolve shift-reduce conflict for one rule by means of |
+| precedence declarations. It has already been checked that the |
+| rule has a precedence. A conflict is resolved by modifying the |
+| shift or reduce tables so that there is no longer a conflict. |
+| |
+| RULENO is the number of the lookahead bitset to consider. |
+| |
+| ERRORS and NERRS can be used to store discovered explicit |
+| errors. |
+`------------------------------------------------------------------*/
+
+static void
+resolve_sr_conflict (state *s, int ruleno, symbol **errors, int *nerrs)
+{
+ symbol_number i;
+ reductions *reds = s->reductions;
+ /* Find the rule to reduce by to get precedence of reduction. */
+ rule *redrule = reds->rules[ruleno];
+ int redprec = redrule->prec->prec;
+ bitset lookahead_tokens = reds->lookahead_tokens[ruleno];
+
+ for (i = 0; i < ntokens; i++)
+ if (bitset_test (lookahead_tokens, i)
+ && bitset_test (lookahead_set, i)
+ && symbols[i]->prec)
+ {
+ /* Shift-reduce conflict occurs for token number i
+ and it has a precedence.
+ The precedence of shifting is that of token i. */
+ if (symbols[i]->prec < redprec)
+ {
+ log_resolution (redrule, i, reduce_resolution);
+ flush_shift (s, i);
+ }
+ else if (symbols[i]->prec > redprec)
+ {
+ log_resolution (redrule, i, shift_resolution);
+ flush_reduce (lookahead_tokens, i);
+ }
+ else
+ /* Matching precedence levels.
+ For left association, keep only the reduction.
+ For right association, keep only the shift.
+ For nonassociation, keep neither. */
+
+ switch (symbols[i]->assoc)
+ {
+ default:
+ abort ();
+
+ case right_assoc:
+ log_resolution (redrule, i, right_resolution);
+ flush_reduce (lookahead_tokens, i);
+ break;
+
+ case left_assoc:
+ log_resolution (redrule, i, left_resolution);
+ flush_shift (s, i);
+ break;
+
+ case non_assoc:
+ log_resolution (redrule, i, nonassoc_resolution);
+ flush_shift (s, i);
+ flush_reduce (lookahead_tokens, i);
+ /* Record an explicit error for this token. */
+ errors[(*nerrs)++] = symbols[i];
+ break;
+ }
+ }
+}
+
+
+/*-------------------------------------------------------------------.
+| Solve the S/R conflicts of state S using the |
+| precedence/associativity, and flag it inconsistent if it still has |
+| conflicts. ERRORS can be used as storage to compute the list of |
+| lookahead tokens on which S raises a syntax error (%nonassoc). |
+`-------------------------------------------------------------------*/
+
+static void
+set_conflicts (state *s, symbol **errors)
+{
+ int i;
+ transitions *trans = s->transitions;
+ reductions *reds = s->reductions;
+ int nerrs = 0;
+
+ if (s->consistent)
+ return;
+
+ bitset_zero (lookahead_set);
+
+ FOR_EACH_SHIFT (trans, i)
+ bitset_set (lookahead_set, TRANSITION_SYMBOL (trans, i));
+
+ /* Loop over all rules which require lookahead in this state. First
+ check for shift-reduce conflict, and try to resolve using
+ precedence. */
+ for (i = 0; i < reds->num; ++i)
+ if (reds->rules[i]->prec && reds->rules[i]->prec->prec
+ && !bitset_disjoint_p (reds->lookahead_tokens[i], lookahead_set))
+ resolve_sr_conflict (s, i, errors, &nerrs);
+
+ if (nerrs)
+ {
+ /* Some tokens have been explicitly made errors. Allocate a
+ permanent errs structure for this state, to record them. */
+ state_errs_set (s, nerrs, errors);
+ }
+ if (obstack_object_size (&solved_conflicts_obstack))
+ {
+ obstack_1grow (&solved_conflicts_obstack, '\0');
+ s->solved_conflicts = obstack_finish (&solved_conflicts_obstack);
+ }
+ if (obstack_object_size (&solved_conflicts_xml_obstack))
+ {
+ obstack_1grow (&solved_conflicts_xml_obstack, '\0');
+ s->solved_conflicts_xml = obstack_finish (&solved_conflicts_xml_obstack);
+ }
+
+ /* Loop over all rules which require lookahead in this state. Check
+ for conflicts not resolved above. */
+ for (i = 0; i < reds->num; ++i)
+ {
+ if (!bitset_disjoint_p (reds->lookahead_tokens[i], lookahead_set))
+ conflicts[s->number] = 1;
+ bitset_or (lookahead_set, lookahead_set, reds->lookahead_tokens[i]);
+ }
+}
+
+
+/*----------------------------------------------------------------.
+| Solve all the S/R conflicts using the precedence/associativity, |
+| and flag as inconsistent the states that still have conflicts. |
+`----------------------------------------------------------------*/
+
+void
+conflicts_solve (void)
+{
+ state_number i;
+ /* List of lookahead tokens on which we explicitly raise a syntax error. */
+ symbol **errors = xnmalloc (ntokens + 1, sizeof *errors);
+
+ conflicts = xcalloc (nstates, sizeof *conflicts);
+ shift_set = bitset_create (ntokens, BITSET_FIXED);
+ lookahead_set = bitset_create (ntokens, BITSET_FIXED);
+ obstack_init (&solved_conflicts_obstack);
+ obstack_init (&solved_conflicts_xml_obstack);
+
+ for (i = 0; i < nstates; i++)
+ {
+ set_conflicts (states[i], errors);
+
+ /* For uniformity of the code, make sure all the states have a valid
+ `errs' member. */
+ if (!states[i]->errs)
+ states[i]->errs = errs_new (0, 0);
+ }
+
+ free (errors);
+}
+
+
+void
+conflicts_update_state_numbers (state_number old_to_new[],
+ state_number nstates_old)
+{
+ state_number i;
+ for (i = 0; i < nstates_old; ++i)
+ if (old_to_new[i] != nstates_old)
+ conflicts[old_to_new[i]] = conflicts[i];
+}
+
+
+/*---------------------------------------------.
+| Count the number of shift/reduce conflicts. |
+`---------------------------------------------*/
+
+static int
+count_sr_conflicts (state *s)
+{
+ int i;
+ int src_count = 0;
+ transitions *trans = s->transitions;
+ reductions *reds = s->reductions;
+
+ if (!trans)
+ return 0;
+
+ bitset_zero (lookahead_set);
+ bitset_zero (shift_set);
+
+ FOR_EACH_SHIFT (trans, i)
+ bitset_set (shift_set, TRANSITION_SYMBOL (trans, i));
+
+ for (i = 0; i < reds->num; ++i)
+ bitset_or (lookahead_set, lookahead_set, reds->lookahead_tokens[i]);
+
+ bitset_and (lookahead_set, lookahead_set, shift_set);
+
+ src_count = bitset_count (lookahead_set);
+
+ return src_count;
+}
+
+
+/*----------------------------------------------------------------.
+| Count the number of reduce/reduce conflicts. If ONE_PER_TOKEN, |
+| count one conflict for each token that has any reduce/reduce |
+| conflicts. Otherwise, count one conflict for each pair of |
+| conflicting reductions. |
++`----------------------------------------------------------------*/
+
+static int
+count_rr_conflicts (state *s, bool one_per_token)
+{
+ int i;
+ reductions *reds = s->reductions;
+ int rrc_count = 0;
+
+ for (i = 0; i < ntokens; i++)
+ {
+ int count = 0;
+ int j;
+ for (j = 0; j < reds->num; ++j)
+ if (bitset_test (reds->lookahead_tokens[j], i))
+ count++;
+
+ if (count >= 2)
+ rrc_count += one_per_token ? 1 : count-1;
+ }
+
+ return rrc_count;
+}
+
+
+/*--------------------------------------------------------.
+| Report the number of conflicts, using the Yacc format. |
+`--------------------------------------------------------*/
+
+static void
+conflict_report (FILE *out, int src_num, int rrc_num)
+{
+ if (src_num && rrc_num)
+ fprintf (out, _("conflicts: %d shift/reduce, %d reduce/reduce\n"),
+ src_num, rrc_num);
+ else if (src_num)
+ fprintf (out, _("conflicts: %d shift/reduce\n"), src_num);
+ else if (rrc_num)
+ fprintf (out, _("conflicts: %d reduce/reduce\n"), rrc_num);
+}
+
+
+/*-----------------------------------------------------------.
+| Output the detailed description of states with conflicts. |
+`-----------------------------------------------------------*/
+
+void
+conflicts_output (FILE *out)
+{
+ bool printed_sth = false;
+ state_number i;
+ for (i = 0; i < nstates; i++)
+ {
+ state *s = states[i];
+ if (conflicts[i])
+ {
+ fprintf (out, _("State %d "), i);
+ conflict_report (out, count_sr_conflicts (s),
+ count_rr_conflicts (s, true));
+ printed_sth = true;
+ }
+ }
+ if (printed_sth)
+ fputs ("\n\n", out);
+}
+
+/*--------------------------------------------------------.
+| Total the number of S/R and R/R conflicts. Unlike the |
+| code in conflicts_output, however, count EACH pair of |
+| reductions for the same state and lookahead as one |
+| conflict. |
+`--------------------------------------------------------*/
+
+int
+conflicts_total_count (void)
+{
+ state_number i;
+ int count;
+
+ /* Conflicts by state. */
+ count = 0;
+ for (i = 0; i < nstates; i++)
+ if (conflicts[i])
+ {
+ count += count_sr_conflicts (states[i]);
+ count += count_rr_conflicts (states[i], false);
+ }
+ return count;
+}
+
+
+/*------------------------------------------.
+| Reporting the total number of conflicts. |
+`------------------------------------------*/
+
+void
+conflicts_print (void)
+{
+ /* Is the number of SR conflicts OK? Either EXPECTED_CONFLICTS is
+ not set, and then we want 0 SR, or else it is specified, in which
+ case we want equality. */
+ bool src_ok;
+ bool rrc_ok;
+
+ int src_total = 0;
+ int rrc_total = 0;
+ int src_expected;
+ int rrc_expected;
+
+ /* Conflicts by state. */
+ {
+ state_number i;
+
+ for (i = 0; i < nstates; i++)
+ if (conflicts[i])
+ {
+ src_total += count_sr_conflicts (states[i]);
+ rrc_total += count_rr_conflicts (states[i], true);
+ }
+ }
+
+ if (! glr_parser && rrc_total > 0 && expected_rr_conflicts != -1)
+ {
+ warn (_("%%expect-rr applies only to GLR parsers"));
+ expected_rr_conflicts = -1;
+ }
+
+ src_expected = expected_sr_conflicts == -1 ? 0 : expected_sr_conflicts;
+ rrc_expected = expected_rr_conflicts == -1 ? 0 : expected_rr_conflicts;
+ src_ok = src_total == src_expected;
+ rrc_ok = rrc_total == rrc_expected;
+
+ /* If there are as many RR conflicts and SR conflicts as
+ expected, then there is nothing to report. */
+ if (rrc_ok & src_ok)
+ return;
+
+ /* Report the total number of conflicts on STDERR. */
+ if (src_total | rrc_total)
+ {
+ if (! yacc_flag)
+ fprintf (stderr, "%s: ", current_file);
+ conflict_report (stderr, src_total, rrc_total);
+ }
+
+ if (expected_sr_conflicts != -1 || expected_rr_conflicts != -1)
+ {
+ if (! src_ok)
+ complain (ngettext ("expected %d shift/reduce conflict",
+ "expected %d shift/reduce conflicts",
+ src_expected),
+ src_expected);
+ if (! rrc_ok)
+ complain (ngettext ("expected %d reduce/reduce conflict",
+ "expected %d reduce/reduce conflicts",
+ rrc_expected),
+ rrc_expected);
+ }
+}
+
+
+void
+conflicts_free (void)
+{
+ free (conflicts);
+ bitset_free (shift_set);
+ bitset_free (lookahead_set);
+ obstack_free (&solved_conflicts_obstack, NULL);
+ obstack_free (&solved_conflicts_xml_obstack, NULL);
+}
Property changes on: bison\src\bison\2.4.1\bison-2.4.1-src\src\conflicts.c
___________________________________________________________________
Added: svn:eol-style
+ LF
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