Add native Windows binary for bison.

bison/src/bison/2.4.1/bison-2.4.1-src/src/conflicts.c

+/* 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);
+}