| 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 < %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 < %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
|
|
|
|
|